1
(what) the heck;(why) in the world;(who) on earth;(where) the hell;(how) the hell
before an interrogative; forms an emphatic question
一体どこで彼に会ったんだ。
Where on earth did you meet him?
2
one object;one body;one unit;one group;one mass
ストライキとは従業員の集団が一体となって就労を拒否することです。
A strike is a mass refusal to work by a body of employees.
3
one form;one style;one format;one fashion
4
one Buddhist image;one carving;one sculpture
5
one corpse;one sample (of bones, remains, etc.)
6
7
strictly speaking;in the first place;originally;to begin with
Other forms
１体 【いったい】 (search-only kanji form)