As many apps, I just stumble upon them when searching for another app, when perusing educational apps, iDevice info or free app offerings.
Define: app was one of those stumbled upon apps. It is simple but provides an easy method to create a vocabulary list from an existing dictionary base that is not dependent on Wi-Fi services unless you want to use Wikipedia, Wiktionary or do a Web Search of the word.
Define: provides a search tool to look up a work typed into the search text box. Once the word is typed it will look up the word and provide a definition. The word is entered into the beginning page of the app in a listing by date, creating a simple vocabulary list of words and definitions at your finger tips in this app. A speak tool is available to read only the word searched, not the definition. If you have Speak Selection turned on in the Accessibility options of your iDevice you will have tools to speak the definition aloud.
For more definitions, selecting the Definitions tool provides you with other uses and definitions of the word. You also have the option of looking up the word in Wiktionary, Wikipedia and by Web Search. A camera in the right upper corner allows you to take a picture or select a photo from your Photos app. If you brought in a picture or image a Media category is listed where the pictures or web clips related to the word are able to be reviewed. I found that if I wanted content from any of the web services it was easier to take a screen shot (Press home button and power button simultaneously) putting the image in the Photo app and ready to use as Media for one of your defined words.
This is a very simple app, but I see application of this app for a student who would benefit from a word list with definition and media that support unfamiliar vocabulary. Although many of the dictionaries allow for a favorites category where you can create a custom word list, this app is simple and provides opportunities to include media with the word and definition. I have some learning disability and ASD students that I believe would benefit from this app, even if it only was on a teachers iPad, allowing them an immediate reference and word definition (with media) for visual learners.
Define: is compatible with iPad, iPhone and iPod Touch and currently is free. There is limited information on the Internet on the app, but can be found in the App Store by searching Define: .
Another tool for your OT iToolkit depending on the ages and needs of your students.