According to dictionary.com, a trio is defined as "any group of three persons or things".
noun, plural trios.
any group of three persons or things.
Trio is a singular noun that refers to a group of people. Is this singular word ambiguous with its plural meaning? This is the sentence that sparked this question:
Without idle chitchat to distract them, the trio was reminded of their missing friend.
The fragment uses the word "them" to refer to the three people. However, should "was" be "were", or is it fine as it is? Since trio means a group of things, yet the word itself is not automatically plural, I find it disconcerting to switch from plural to singular pronouns.