Noun
(mathematics) A form (expression) that does not use limits, implicitly or explicitly.
There is no known representation of π in closed form: each expression for it includes an integral, an infinite series, or an infinite continued fraction.
(mathematics) A differential form whose exterior derivative is zero.
(poetry) A type of poetry with regular structure, such as meter or a rhyming pattern.
(poetry) Trobar clus.
Used other than figuratively or idiomatically: see closed, form.
If ω is a closed form, then dω=0.