To overwinter is to get through the winter alive, or to help something get through the winter.

To overwinter這個動詞 is意思是 to get through the winter撐過冬天 alive還活著，or或者是 to help something幫助某個東西 get through the winter撐過冬天

Insects overwinter under bark. Some birds overwinter in a warmer place. Gardeners overwinter young plants in a greenhouse — they make it possible for them to live until spring.

Insects昆蟲 overwinter撐過冬天 under bark靠在樹皮底下。Some birds有些鳥 overwinter撐過冬天 in a warmer place到比較溫暖的地方。Gardeners園丁 overwinter讓 young plants幼苗撐過冬天 in a greenhouse在溫室裡 — they make it possible for them讓牠們 to live until spring能活到春天

The word is at home in nature, farming, and biology, not in how was your weekend talk. Though actually, spend the winter and survive the winter are fine in ordinary speech; overwinter just packs the idea into one verb, with a slightly scientific feel.

The word這個字 is at home很自然地用 in nature, farming, and biology在自然、農業和生物學裡，not而不是 in how was your weekend talk用在「你週末過得如何」這種閒聊裡。Though actually不過其實，spend the winter and survive the winter'spend the winter'和'survive the winter' are fine in ordinary speech在日常說法裡都很自然；overwinter這個字 just packs the idea into one verb只是把意思濃縮進一個動詞裡，with a slightly scientific feel帶點科學味

The over- here is not too much. It is the through / across-the-season kind, like living over the winter. That is a different job from the over- in overuse.

The over- here這裡的over- is not too much不是「太多」的意思，It is而是 the through / across-the-season kind「貫穿、跨過一整季」的那種，like living over the winter就像撐過整個冬天那樣。That is這是 a different job不一樣的功能 from the over- in overuse跟overuse裡的over-不同