1A sharp, pointed projection on a plant or animal — a thorn, spine or prickle, as on a rose, a cactus or a fish's fin. Normally written in kana: both kanji (刺, 棘) are non-standard for this reading, and the katakana form トゲ is common when talking about plants and animals.
バラの茎にはとげがたくさんあるので、切るときは手袋をしたほうがいい。
Rose stems have a lot of thorns, so you should wear gloves when you cut them.
サボテンのトゲは意外に鋭いので、うっかり触ると危ない。
Cactus spines are surprisingly sharp, so it's dangerous to touch one carelessly.
この魚はひれにトゲがあるので、扱うときは注意が必要だ。
This fish has spines on its fins, so you need to be careful handling it.
とげのある枝を素手でつかんで、手を傷つけてしまった。
I grabbed a thorny branch with my bare hands and hurt myself.
2A small sharp object that has lodged itself in your skin or throat — a splinter, or something like a fish bone caught in the throat.
木の板を触ったら、指にとげが刺さってしまった。
I touched a wooden board and got a splinter in my finger.
ピンセットで足の裏のとげを抜いてもらった。
I had the splinter pulled out of the sole of my foot with tweezers.
小さなとげでも、抜かずに放っておくと化膿することがある。
Even a tiny splinter can get infected if you leave it in.
3A barb in what someone says — the sharp, prickly edge in words or tone that stings the listener. Used in phrases like とげのある言い方 (a barbed way of putting it).
彼女の言い方にはいつもとげがあって、みんな身構えてしまう。
There's always a barb in the way she says things, and it puts everyone on their guard.
注意はしたが、なるべくとげのある言葉にならないよう気をつけた。
I did point it out, but I was careful to keep my words from sounding barbed.
「別にいいけど」という一言に、少しとげを感じた。
I caught a slight edge in her 「it's fine, whatever」.