Picture a fine gesture made where people can see it. Someone steps forward when it would be easier to stand still, and afterwards others describe what he did. That is the feel the word keeps in both of its directions: into danger and being given a medal for it, and up to a chair, a door or a compliment because the manners of the time ask for it. In both, the behaviour is meant to be noticed and is judged by — which is why the plural gallantries can count the separate gestures one by one.
From French galanterie, that is gallant + -ry: the noun for the way a gallant person behaves. Gallant itself carries both brave and courteous, which is why the noun runs in two directions.
來自法文 galanterie，也就是 gallant 加上 -ry：把「gallant 的那種表現」變成一個名詞。gallant 本身同時帶著勇敢和殷勤有禮兩種味道，所以名詞也跟著分成兩條路。這是字的組成，不是在說哪一條先出現。
Wiktionary etymology supplied in this packet: 'From French galanterie, equivalent to gallant + -ry.'
From the picture
對女士的殷勤
把漂亮的舉動從危險場合搬到日常場合：往前站一步的不是去救人，是去開門、讓座、說一句好聽的話。這是理解上的連結，不是在說歷史上哪個意思先有。
noun · C1
Polite, attentive behaviour shown by men toward women — opening doors, offering a seat, paying compliments — as part of a traditional code of courteous manners.
（男士對女士的）殷勤有禮
noun · C1
Brave behaviour in a dangerous situation, especially in a battle; the word is used most often when that bravery is formally recognised, as with a medal.
英勇