Generally, About, General, Gist
adverb, noun, の adjective
If all you can see is the big body of something, then you'll only get a general idea of what it is. You'll be able to say that it's generally a certain way, but that's about all. You'll get the gist, but no more.
だいたい
This is a jukugo word, which usually means on'yomi readings from the kanji. Since 大 has two on'yomi readings, here's a mnemonic to help you remember which one to use: Generally, it's a bad idea to dye your ties (だいたい). The tie police isn't a big fan of it, and you wouldn't wanna get arrested!
大体は正しいです。
It's mostly correct.
右手と左手の大きさは大体同じです。
Right and left hands are about the same size.
大体三日かかります。
It takes about three days.