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 |
|---|---|---|
| Sinclair | 8 | 1502 (cote); 1506 (barras); 1524 (chandeler, cosing, cum); 1529 (bern); 1604 (cunstar); 1613 (butter) |
| Synclar | 4 | 1510 (conquis); 1544 (chet); 1553 (bailȝe); 1584 (col-) |
| Sinclare | 2 | 1473 (banis); 1542 (copper) |
| Sincler | 2 | 1516 (deand); 1538 (burse) |
| Sinclar | 1 | 1579 (collig) |
| Sinclere | 1 | 1516 (cousinace) |
| Sinklere | 1 | 1511 (artaillery) |
| Syngclare | 1 | 1460 (cosingnace) |