diff --git a/index.html b/index.html
index b93d398..cfdb6b1 100644
--- a/index.html
+++ b/index.html
@@ -49,8 +49,8 @@
 
   <main>
     <aside id="sideColumn">
-      <form id="wordForm" onsubmit="function(e){e.preventDefault();return false;}">
-        <label>Word<br>
+      <form id="wordForm">
+        <label>Word<span class="red">*</span><br>
           <input id="wordName">
         </label>
         <label>Pronunciation<a class="label-button">IPA Chart</a><br>
@@ -59,12 +59,14 @@
         <label>Part of Speech<br>
           <select id="wordPartOfSpeech" class="part-of-speech-select"></select>
         </label>
-        <label>Definition<br>
+        <label>Definition<span class="red">*</span><br>
           <input id="wordDefinition" placeholder="Equivalent words">
         </label>
-        <label>Details<a class="label-button">Maximize</a><br>
+        <label>Details<span class="red">*</span><a class="label-button">Maximize</a><br>
           <textarea id="wordDetails" placeholder="Markdown formatting allowed"></textarea>
         </label>
+        <div id="wordErrorMessage"></div>
+        <a class="button" id="addWordButton">Add Word</a>
       </form>
     </aside>
     
diff --git a/src/helpers.js b/src/helpers.js
index b2d7e72..f3416c6 100644
--- a/src/helpers.js
+++ b/src/helpers.js
@@ -3,24 +3,26 @@ export function cloneObject(object) {
 }
 
 export function removeTags(html) {
-var tagBody = '(?:[^"\'>]|"[^"]*"|\'[^\']*\')*';
-
-var tagOrComment = new RegExp(
-  '<(?:'
-  // Comment body.
-  + '!--(?:(?:-*[^->])*--+|-?)'
-  // Special "raw text" elements whose content should be elided.
-  + '|script\\b' + tagBody + '>[\\s\\S]*?</script\\s*'
-  + '|style\\b' + tagBody + '>[\\s\\S]*?</style\\s*'
-  // Regular name
-  + '|/?[a-z]'
-  + tagBody
-  + ')>',
-  'gi');
-  var oldHtml;
-  do {
-    oldHtml = html;
-    html = html.replace(tagOrComment, '');
-  } while (html !== oldHtml);
-  return html.replace(/</g, '&lt;');
+  if (html) {
+    var tagBody = '(?:[^"\'>]|"[^"]*"|\'[^\']*\')*';
+    var tagOrComment = new RegExp(
+      '<(?:'
+      // Comment body.
+      + '!--(?:(?:-*[^->])*--+|-?)'
+      // Special "raw text" elements whose content should be elided.
+      + '|script\\b' + tagBody + '>[\\s\\S]*?</script\\s*'
+      + '|style\\b' + tagBody + '>[\\s\\S]*?</style\\s*'
+      // Regular name
+      + '|/?[a-z]'
+      + tagBody
+      + ')>',
+      'gi');
+    var oldHtml;
+    do {
+      oldHtml = html;
+      html = html.replace(tagOrComment, '');
+    } while (html !== oldHtml);
+    return html.replace(/</g, '&lt;');
+  }
+  return html;
 }
diff --git a/src/js/setupListeners.js b/src/js/setupListeners.js
index f486fb4..fe8c600 100644
--- a/src/js/setupListeners.js
+++ b/src/js/setupListeners.js
@@ -1,9 +1,13 @@
 import {showSection} from './displayToggles';
 import { renderWords } from './render';
+import { validateWord, addWord } from './wordManagement';
+import { removeTags } from '../helpers';
+import { getNextId } from './utilities';
 
 export default function setupListeners() {
   setupDetailsTabs();
   setupSearchBar();
+  setupWordForm();
 }
 
 function setupDetailsTabs() {
@@ -41,4 +45,34 @@ function setupSearchBar() {
   openSearchModal.addEventListener('click', () => {
     document.getElementById('searchModal').style.display = 'block';
   });
+}
+
+function setupWordForm() {
+  const wordForm = document.getElementById('wordForm'),
+    addWordButton = document.getElementById('addWordButton');
+  wordForm.addEventListener('submit', event => {
+    // Allow semantic form and prevent it from getting submitted
+    event.preventDefault();
+    return false;
+  });
+  addWordButton.addEventListener('click', () => {
+    const name = document.getElementById('wordName').value,
+      pronunciation = document.getElementById('wordPronunciation').value,
+      partOfSpeech = document.getElementById('wordPartOfSpeech').value,
+      definition = document.getElementById('wordDefinition').value,
+      details = document.getElementById('wordDetails').value;
+
+    const word = {
+      name: removeTags(name).trim(),
+      pronunciation: removeTags(pronunciation).trim(),
+      partOfSpeech: removeTags(partOfSpeech).trim(),
+      simpleDefinition: removeTags(definition).trim(),
+      longDefinition: removeTags(details).trim(),
+      wordId: getNextId(),
+    };
+
+    if (validateWord(word)) {
+      addWord(word);
+    }
+  });
 }
\ No newline at end of file
diff --git a/src/js/utilities.js b/src/js/utilities.js
index 7ae88c6..2069806 100644
--- a/src/js/utilities.js
+++ b/src/js/utilities.js
@@ -1,5 +1,12 @@
 import { cloneObject } from '../helpers';
 
+export function getNextId() {
+  const lastId = window.currentDictionary.words.reduce((highestId, word) => {
+    return (word.wordId && word.wordId) > highestId ? word.wordId : highestId;
+  }, 0);
+  return lastId + 1;
+}
+
 export function getWordsStats() {
   const {words, partsOfSpeech} = window.currentDictionary;
   const {caseSensitive} = window.currentDictionary.settings;
diff --git a/src/js/wordManagement.js b/src/js/wordManagement.js
new file mode 100644
index 0000000..2139c4a
--- /dev/null
+++ b/src/js/wordManagement.js
@@ -0,0 +1,39 @@
+import { renderWords } from "./render";
+import { wordExists } from "./utilities";
+
+export function validateWord(word, wordId = false) {
+  const errorElementId = wordId === false ? 'wordErrorMessage' : 'wordErrorMessage_' + wordId,
+    errorElement = document.getElementById(errorElementId);
+  let errorMessage = '';
+  
+  if (word.name === '') {
+    errorMessage += '<p class="bold red">Word field must not be blank.</p>';
+  }
+  if (word.simpleDefinition === '' && word.longDefinition === '') {
+    errorMessage += '<p class="bold red">You must enter Definition or Details.</p>';
+  }
+
+  const { allowDuplicates, caseSensitive } = window.currentDictionary.settings;
+  if (!allowDuplicates) {
+    const foundDuplicate = wordExists(word.name, true);
+    if (foundDuplicate !== false) {
+      errorMessage += `<p class="bold red">"<a href="#${foundDuplicate}">${word.name}</a>" already exists, and "Allow Duplicates" is turned off.${!caseSensitive ? ' <em>(Case sensitivity is turned also off)</em>' : ''}</p>`;
+    }
+  }
+
+  errorElement.innerHTML = errorMessage;
+  return errorMessage === '';
+}
+
+export function addWord(word) {
+  const { sortByDefinition } = window.currentDictionary.settings;
+  const sortBy = sortByDefinition ? 'simpleDefinition' : 'name';
+
+  window.currentDictionary.words.push(word);
+  window.currentDictionary.words.sort((wordA, wordB) => {
+    if (wordA[sortBy] === wordB[sortBy]) return 0;
+    return wordA[sortBy] > wordB[sortBy] ? 1 : -1;
+  });
+
+  renderWords();
+}
diff --git a/src/styles/_elements.scss b/src/styles/_elements.scss
index 7399bb9..f5e451d 100644
--- a/src/styles/_elements.scss
+++ b/src/styles/_elements.scss
@@ -1,3 +1,13 @@
+p, span {
+  &.red {
+    color: $red;
+  }
+
+  &.bold {
+    font-weight: bold;
+  }
+}
+
 .tag {
   padding: 3px 9px;
   border: $border;
diff --git a/src/styles/_structure.scss b/src/styles/_structure.scss
index 954ea68..8bc4531 100644
--- a/src/styles/_structure.scss
+++ b/src/styles/_structure.scss
@@ -51,6 +51,8 @@
   background-color: $light;
   border: $border;
   border-radius: 5px;
+  max-height: 80%;
+  overflow-y: auto;
 
   label {
     display: block;