A River Mouth Is Where It Ends, Not Begins
A mouth is the opening through which food is taken. Rivers, caves and bottles all have mouths, and a river's is at its end.
A mouth is the opening through which an animal takes food, and by extension any similar opening. A river's mouth is where it empties into the sea, which reverses the anatomical logic: a body's mouth takes things in, a river's puts them out. The naming follows shape rather than function. The plural pronunciation changes the final sound: one mouth, two mouths with a voiced th.
- A body opening. *Open your mouth.*
- A river's outlet. *The mouth of the Thames.*
- An entrance. *The mouth of the cave.*
- To speak silently. *He mouthed the words.*
- Estuary — a tidal river mouth. *An estuary.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | mouth | An open mouth. |
| Plural | mouths | Many mouths. |
| Verb | mouth | Mouth the words. |
| Adjective | oral | Oral health. |
| Old English | muth | Mouth. |
- The river's mouth widens into an estuary.Geography.
- He mouthed an apology across the room.Verb.
- Many mouths to feed.Idiom.
Mouth idioms
- By word of mouth — spread in speech
- Down in the mouth — dejected
- Put words in someone's mouth — attribute things they did not say
- Look a gift horse in the mouth — question a favour, from checking teeth
- Butter wouldn't melt in her mouth — falsely innocent
Old English *muth*, from a Germanic root shared with German *Mund*, related to Latin *mentum*, chin.
Why is a river's mouth at the sea?
The name follows the shape of an opening rather than the direction of flow, so it marks where the river ends.
Why does the th change in mouths?
A small group of English nouns voice the final consonant in the plural, like path and paths or bath and baths.