The following information is taken from the Dictionary of the Older Scottish Tongue, available online at http://www.dsl.ac.uk/index.html. This is a work in progress.
| Spelling | Number | Dates & headers |
|---|---|---|
| Abirbrothoc | 3 | 1394 (chapiter); 1488 (crowner); 1497 (chamerlane) |
| Abirbrothok | 1 | 1575 (debatable) |