The compound "wide-mouth" is a straightforward combination of two native English words. "Wide" descends from the Proto-Germanic wīdaz, itself from the Proto-Indo-European root wi- meaning "apart, asunder," conveying a sense of separation and thus breadth. "Mouth" originates from Proto-Germanic munþaz, with an uncertain deeper Indo-European ancestry, but consistently referring to an opening. The compound's logic is transparently literal, directly describing the physical characteristic of having a broad oral or figurative opening. Its formation follows the common Germanic pattern of adjective-noun compounding to create a descriptive term, retaining the core meanings of its components with minimal semantic shift.

Structure: wide (broad) + mouth (oral opening) wide: From Old English wīd, meaning "spacious, broad, long". It functions as an adjective describing extent. mouth: From Old English mūþ, meaning "opening, door, gate, mouth of a person or animal". It functions as a noun denoting an opening.