long. is the written short form of longitude: how far east or west a place is on the Earth, measured in degrees from an imaginary line through Greenwich in London.

long. is the written short form of longitudelong.是longitude（經度）的書面縮寫：how far east or west a place is on the Earth一個地方在地球上偏東或偏西多遠，measured in degrees from an imaginary line through Greenwich in London以經過倫敦格林威治的假想線為基準，用度數來量。

You meet it on maps, in GPS, and in geography homework, often next to lat. (latitude, how far north or south). A typical line looks like “lat. 25° N, long. 121° E” for Taipei.

You meet it on maps, in GPS, and in geography homework地圖、GPS和地理作業裡都會遇到它，often next to lat.常常跟lat.（緯度）放在一起。(latitude, how far north or south)（latitude是緯度，指偏北或偏南多遠）。A typical line looks like "lat. 25° N, long. 121° E" for Taipei台北的典型寫法會像「lat. 25° N, long. 121° E」這樣。

You almost never say “long” out loud to mean this; when you speak, you say the full word longitude. The little dot is there to show it is an abbreviation, not the ordinary adjective long (as in a long road), and not the verb long (I long for home).

You almost never say "long" out loud to mean this要口頭表達這個意思時幾乎不會說「long」；when you speak, you say the full word longitude說話時會講完整的「longitude」。The little dot is there to show it is an abbreviation那個小黑點是用來標示這是縮寫，not the ordinary adjective long (as in a long road)不是普通形容詞的「long」（像a long road裡那樣），and not the verb long (I long for home)也不是動詞的「long」（像I long for home裡那樣，意思是渴望）。

On a globe, lines of longitude run from pole to pole; the number tells you the east–west slot.

On a globe, lines of longitude run from pole to pole在地球儀上，經線是從一極連到另一極的；the number tells you the east–west slot數字則告訴你東西方向的位置。