The prepositions below and under can both mean ‘lower than‘.
- Look in the cupboard below/under the sink.
We prefer below when one thing is not directly under another.
- The climbers stopped 300m below the top of the mountain.
- A moment later the sun had disappeared below the horizon.
We prefer under when something is covered or hidden by what is over it, and when things are touching.
- I think the eat’s under the bed.
- What are you wearing under your sweater?
- The whole village is under water. (NOT … below water.)
Below is used in measurements of temperature and height, and in other cases where we think of a vertical scale.
- The temperature is three degrees below zero.
- Parts of Holland are below sea level.
- The plane came down below the clouds.
- She’s well below average in intelligence. ~
We usually use under, not below, to mean ‘less than’ or ‘younger than‘.
- There were under twenty people at the lecture.
- You can’t see this film if you’re under 18.
Underneath is sometimes used as a preposition instead of under, but only for physical position.
- There’s a mouse under(neath) the piano.
- He’s still under 18. (NOT …
Beneath is used mostly in a rather literary style.
- The ship sank slowly beneath the waves.
- It is common before abstract nouns in some fixed expressions.
- He acts as if I was beneath his notice. (= not worth considering)
- Her behaviour is beneath contempt. (= really disgraceful)
Below can be used as an adverb.
- We looked over the cliff at the waves crashing on the rocks below.
Under can be used as an adverb particle (see 20) with some verbs.
- A lot of businesses are going under because of the economic crisis.
In other cases we prefer underneath for adverbial use.
- I can’t take my sweater off – I haven’t got anything on underneath.
anything on under)
In a book or a paper, see below means ‘look at something written later’