From WordNet (r) 3.0 (2006):
fill in
v 1: supply with information on a specific topic; "He filled me
in on the latest developments"
2: represent the effect of shade or shadow on [syn: shade,
fill in]
3: be a substitute; "The young teacher had to substitute for the
sick colleague"; "The skim milk substitutes for cream--we are
on a strict diet" [syn: substitute, sub, stand in,
fill in]
4: write all the required information onto a form; "fill out
this questionnaire, please!"; "make out a form" [syn:
complete, fill out, fill in, make out]