Q. According to Merriam-Webster, “than” can function as a conjunction or a preposition. If using title case, would you capitalize “than” in the following title? “There Is More Than One Path to a Successful Meal.” I think so, but I’m not sure what part of speech “than” is in expressions like “more than” and “less than.” Thanks!
A. When than is followed by a noun that acts as its object, then it’s a preposition and can be lowercased in a title; if it’s instead followed by a clause (with a subject and a verb—though the verb is sometimes omitted but understood), then assume it’s a conjunction and give it a capital T.
In your example, where the noun path is the object of the preposition than, you’d use lowercase for the latter:
“There Is More than One Path to a Successful Meal”
But in the following example, where than is followed by a clause and is therefore a conjunction, you’d apply a capital T:
“A Successful Meal Requires More Than I Bargained For”
It might be easier to make an exception and capitalize than even when it’s acting as a preposition rather than as a conjunction (see CMOS 5.189 for an explanation of how these two uses differ). But until that dream becomes a reality (19th edition, maybe?), you’ll need to figure out the grammar before deciding what to do.