Slang 俚語

Single as a slang means:

1. (n.) One dollar; a dollar bill:  I don't have enough singles in the register to get me through the morning.
2. (n.) an unmarried person (Usually plural.): I'm holding a little party for singles.

 這個俚語字有兩個意思：1. (名詞) 一元；一元鈔票： 我沒有足夠的一元在收銀機裡讓我度過早上。 2. (名詞) 一位未婚者 (通常是用複數)：我正在舉辦一個小型的單身宴會。

Reference: 

• Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition.
  Copyright 2007. Published by McGraw Hill.