A colleague asked, “What verb would you use with ‘a variety of terms…’: is or are?”
The answer is that if you’re referring to what the various terms are doing, it’s are; if you’re referring to the variety qua variety, it’s is. Probably you want are:
A variety of terms are used. (Meaning several diverse terms are used.)
A variety of terms is used. (Meaning a specific variety is used – e.g., they’re all vulgar.)
A variety of flowers were on the table. (Assorted flowers were on the table.)
A variety of flowers was on the table. (One specific variety was on the table – presumably I don’t know what it’s called, or I would have said so.)
Generally, you’ll use the is when discussing the variety more in the abstract:
The board was discussing what herbaceous emblem to use for the society. A variety of flowers was on the table, as was a variety of grass, as well as the larch.
But very often a variety of is used as an indefinite plural quantifier, and so takes the plural, just like a lot in A lot of people are coming and a bunch in There are a bunch of questions I want to ask (as opposed to discrete singular entities, as in A lot of land was the subject of the dispute and There is a bunch of flowers on the table).
