Hi karyl70,
I understand you are having an issue with Pages autocorrecting a word you want to keep. The article below explains some options in the Mac operating system to ignore an autocorrection. Also, if it is a word that you use often, you can add it to your dictionary so you won't be asked again. These changes will affect all programs that use the dictionary, not just Pages.
OS X Yosemite: Check spelling and grammar
https://support.apple.com/kb/PH18451?locale=en_US
In many OS X apps, spelling is checked while you type, and mistakes are automatically corrected. You can turn off these features, and use other options while typing emails, messages, or documents.
Ignore suggestions: Press the Escape key, then continue typing.
Undo autocorrections: An automatically corrected word is briefly underlined in blue. To revert to your original spelling, put the insertion point after the word to show your original spelling, then choose your spelling. You can also Control-click the word to show your spelling, then choose it.
For a specific app: In the app, choose Edit > Spelling and Grammar > Correct Spelling Automatically (it’s off when a checkmark isn’t shown).
For all apps: Choose Apple menu > System Preferences, click Keyboard, click Text, then deselect the “Correct spelling automatically” checkbox.
Add words to the spelling dictionary:
Control-click a word, then choose Learn Spelling. The word won’t be flagged as misspelled in any document.
Cheers,
- Judy