I post this in case any language learners out there haven't discovered the app yet. Having an offline dictionary on the go is invaluable, and while most other Thai dictionaries for iOS are based on the LEXiTRON resource (
http://lexitron.nectec.or.th/), which is really meant for Thais, this app is based on the crowd-sourced material of Thai-language.com, which is meant for English-speaking learners of Thai.