Definition of third man
1
: an offside fielding position in cricket usually near the boundary and roughly in line with third slip and the striker;
also
: a player fielding in this position
2
[translation of Greek tritos anthrōpos]
: a logical paradox in which the attempt to pass from one thing to another or to relate one conception to another reveals the necessity of a third and intervening thing or conception and hence leads to an infinite regress 
