1Tea — the beverage made from tea leaves (e.g., green tea, black tea).
朝ごはんに茶を一杯飲むのが習慣だ。
I have a cup of tea with breakfast every morning.
食後に熱い茶をもう一杯どうですか。
Would you like another cup of hot tea after the meal?
喫茶店で抹茶ラテを頼んだら、とても美味しかった。
I ordered a matcha latte at the café and it was very tasty.
2The tea plant itself (Camellia sinensis).
この山では昔から茶を栽培している。
They have been cultivating tea on this mountain for a long time.
3The preparation or making of tea — the act of brewing/whisking tea; can refer to tea ceremony practices.
茶の作法を習っているので、来週のお点前に参加する。
I'm learning tea ceremony etiquette, so I'll take part in next week's tea performance.
4A color — brown. Often called 'chairo' (茶色), but sometimes abbreviated as 'cha' (茶).
彼は茶のコートを着ていたので、すぐに見つけられた。
He was wearing a brown coat, so I found him quickly.
髪を茶に染めてイメージを変えた。
I dyed my hair brown to change my look.
5An archaic meaning: mockery, or treating something lightly in a teasing way. Entirely unused as a standalone noun in modern Japanese; the sense survives only in the verb 茶化す.