couldnt

Couldnt is a nonstandard spelling of the English contraction couldn't, produced when the apostrophe is omitted. The standard form is couldn't, used for the negative form of could (could not) or its perfect variant could not have. The contraction reflects the general pattern of English negation by combining could with not, with the apostrophe indicating the omitted letters.

Contractions such as couldn't originated in Early Modern English as writers shortened phrases like could not. The resulting form could not merely signals the same meaning as the two-word version, but ties the words together to create a more fluid, spoken style in informal writing and dialogue.

Usage and context are important. Couldn't is widely accepted in informal writing, fiction, dialogue, and most edited prose. The form couldnt, without the apostrophe, is typically considered incorrect in formal contexts and may be seen as a typographical error or a constraint of systems that strip punctuation. In digital contexts such as programming, data entry, or search queries where punctuation is disallowed or normalized, couldnt may appear as a string, though it does not carry the standard contraction meaning in code and should be handled carefully for clarity.

Related terms include cannot (the non-contracted form), can't (the informal contraction corresponding to cannot), and could not (the two-word version). Understanding the distinction between the contracted form and its nonstandard variant helps in choosing appropriate spelling based on formality and medium.