The Reginald Punnett Wikipedia article quotes from the 31 March 1901
British Census as follows:
Reginald Crundall Punnett Age:26. Estimated Birth Year abt 1875. Relationship:Boarder. Where born:Tonbridge, Kent, England. Address 83 North Street.FIFE.Scotland. Occupation:Lethuel In Zoology...
The article says Punnett worked as a demonstrator and part-time lecturer at University of St. Andrew's at a time between 1898 to 1902, so lethuel may refer to demonstrator and/or part-time lecturer. However, I haven't been able to verify the meaning, either online or in printed works such as Webster's Third New International Dictionary. What might the definition of the word be?
Update: The Wikipedia page refers to "31 March 1901 Census" and I wrote "31 March 1901 British Census" in my question. I've now struck out British due to zpletan's census-records-of-Scotland comment.