Normal; ordinary — not special, common or standard.
彼は普通の会社員だ。
He is an ordinary office worker.
普通サイズのシャツをください。
Please give me a regular/standard size shirt.
これは普通の会話で使う表現だ。
This is an expression used in everyday conversation.
As an adverb meaning normally, usually, or generally.
普通は朝ごはんを食べます。
I usually eat breakfast.
普通ならもっと時間がかかるはずだ。
Normally it should take more time.
彼は普通あまり人前で話さない。
He normally doesn't speak much in public.
The train type 'futsu' — a local train that stops at every station (used as an abbreviation).
この電車は普通（各駅停車）です。
This train is a local (stops at every station).
新幹線ではなく普通で行くから時間がかかるよ。
I'm taking the local train, not the bullet train, so it will take longer.