One professor has written a 3-letter word on the blackboard, and explained that it was a 3-digit number in base 26, using A=0, B=1, C=2, etc.

A second professor figured what the decimal equivalent was, and then used the first professor's notation to write it: 0=A, 1=B, 2=C, etc.

He noticed that the result was also a common 3-letter word.

What were the two words?

...or, perhaps I should say at least five possibilites. The word fid is a specialized term, so it and its paired word perhaps may not be a valid solution.  Though informal, I do consider deb to be a common word.  Though denoted as words in some dictionaries, commonly used acronymic words like BLT and ATM might be excluded, but are included here as possibilities:

103
Professor 1: ADZ - a heavy curved chisel-like tool  
Professor 2: BAD - evil; not good

301
Professor 1: ALP - a high mountain  
Professor 2: DAB - to pat or tap gently; a European flatfish

341
Professor 1: AND - a conjunction [with; also; then; added to]  
Professor 2: DEB - (informal) a debutante

506
Professor 1: ATM - unattended machine for dispensing money   
Professor 2: FAG - to tire or exhaust; (slang) a cigarette

583
Professor 1: AWL - an instrument for piercing small holes  
Professor 2: FID - (Nautical) a stout bar cross the trestletrees of a lower spar fixed to support the upper spar

783  
Professor 1: BED - a piece of furniture upon which one sleeps
Professor 2: HID -  concealed from sight

784
Professor 1: BEE - a type of insect; a social gathering for a task 
Professor 2: HIE - to hasten

981
Professor 1: BLT - a bacon, lettuce and tomato sandwich 
Professor 2: JIB - a triangular sail; the boom of a derrick; balk

Edited on September 17, 2006, 12:43 am

Posted by Dej Mar on 2006-09-16 21:53:48