• n. 焦點；中心；清晰；焦距
• vt. 使集中；使聚焦
• vi. 集中；聚焦；調節(jié)焦距
• n. (Focus)人名；(瑞典)福庫斯

來自拉丁語focus, 火爐，引申詞義家，集中點。在1604年德國數學家Johannes Kepler用該詞來指數學意義上的聚焦。進一步可能來自PIE*bhe, 照明，發(fā)光，詞源同beacon.

focus

focus: [17] Latin focus meant ‘fireplace’, and in post-classical times it came to be used for ‘fire’ itself – hence French feu, Italian fuoco, Spanish fuego, all meaning ‘fire’, and hence too the English derivatives fuel and fusillade. The first writer known to have used it in its modern sense ‘point of convergence’ was the German astronomer Johannes Kepler, in 1604, but the reason for his choice of word is not clear.

It may have been some metaphorical notion of the ‘hearth’ symbolizing the ‘centre of the home’, but it has also been suggested that it may have been preceded and inspired by the use of focus for the ‘burning point’ of a mirror (not actually recorded until somewhat later). The philosopher Thomas Hobbes appears to have introduced the term into English, in 1656. A medieval Latin derivative of focus was focārius, from which French got foyer ‘hearth, home’, borrowed by English in the 19th century for a public entrance hall or lobby.
=> foyer, fuel, fusillade

focus (n.)

1640s, "point of convergence," from Latin focus "hearth, fireplace" (also, figuratively, "home, family"), which is of unknown origin. Used in post-classical times for "fire" itself; taken by Kepler (1604) in a mathematical sense for "point of convergence," perhaps on analogy of the burning point of a lens (the purely optical sense of the word may have existed before Kepler, but it is not recorded). Introduced into English 1650s by Hobbes. Sense transfer to "center of activity or energy" is first recorded 1796.

focus (v.)

1775 in optics, "bring into focus" (transitive); 1807 in the figurative sense, from focus (n.). Intransitive use by 1864, originally in photography. Related: Focused; focusing; less commonly focussed; focussing.

1. In the background, in soft focus, we see his smiling wife.

在背景部分，我們可以看到他妻子面帶微笑的蒙影像。

來自柯林斯例句

2. Their talks are expected to focus on arms control.

他們的會談預計會集中討論軍備控制問題。

來自柯林斯例句

3. These issues were brought into sharp focus by the Gulf crisis.

海灣危機讓這些問題備受關注。

來自柯林斯例句

4. Today he was able to focus his message exclusively on the economy.

今天他得以將主題全部集中在經濟方面。

來自柯林斯例句

5. They focus on overt discrimination rather than insidious aspects of racism.

他們關注的是公開的歧視，而不是種族主義的一些潛在問題。

來自柯林斯例句