Dear Geist,
What’s with fresh water (fresh-water, freshwater) and salt water (salt-water, saltwater)? Can’t the educators and publishers and dictionary writers get together on spelling and punctuation? As a marine biology student I have to deal with this issue every single day and no relief in sight.
—Audra Bradye, Hamilton ON
Dear Audra,
Salt water (two words) is a noun naming the water. Saltwater and salt-water are adjectives meaning consisting of, relating to or living in salt water—saltwater mammals, saltwater pond, saltwater taffy, etc.—and both are correct. Your university should have a style guide that lists preferences. Meanwhile, as you’ve noticed, all three forms are used for both the noun and the adjective, sometimes within the same document—a practice that can be inelegant and distracting, but seldom introduces ambiguity. Some book publishers’ style guides specify using saltwater for all uses, a sensible, economical solution.
—The Editors