Under - below

The use of the prepositions 'under' and 'below' sometimes presents difficulties for non-native speakers of English. Here are some guidelines:

• Both prepositions are used to indicate the spatial position of one object relative to another. However, 'under' is used when one object is directly below or underneath another, as in 'The murderer concealed the body of his victim under the floorboards', 'He stored his suitcase out of sight under the bed', and 'I found the cheque I thought I had lost under a pile of books'. When one object is on a lower level than another but not directly beneath it, 'below' is used, as in 'Below the terrace there is an extensive formal garden', 'The sun sank below the horizon', and 'The village lies in a valley below a range of chalk hills'.

• Both prepositions are used, especially with numerals, in the context of measurements, estimates, and the like, and in these contexts they are sometimes interchangeable. However, 'under' in this context simply means 'less than', as in 'There were under thirty people at the meeting', 'It is impossible to live in London on an income of under £20,000 a year', and 'Everything in this shop costs under a pound'. The use of 'below' often presupposes measurement against a vertical scale and may suggest a falling short of or failure to reach a specified level or expected standard, as in 'The temperature last night was 3° below zero', 'Students who score below 40% in this examination will not be allowed to continue the course', 'At the time of the accident he was driving well below the speed limit', and 'Her weight is below average for her age'.

• 'Under', but never 'below', is used to mean:

(a) subject to the authority, control, or supervision of another person, as in 'His uncle fought in the North Africa campaign under Field Marshal Montgomery', 'He was a member of the cabinet under four prime ministers', 'He studied for several years under the great German scholar Professor von Hindenberg';

(b) in a particular category within a classificatory scheme, as in 'You will find that book under Astronomy' and 'I have classified those papers under Miscellaneous';

(c) using the name of, as in 'Ruth Rendell wrote A Dark-Adapted Eye under the pseudonym Barbara Vine'.

• 'Below', but never 'under', is used to mean:

(a) to the south of, as in 'Hackforth is just below Catterick on the A1';

(b) downstream from, as in 'The body was recovered from the Thames below Tower Bridge'.

• 'Under', but never 'below', forms the prefix to many verbs, such as 'underachieve', 'undercut', 'underestimate', 'underpay', 'understate'; adjectives, such as 'underage', 'underarm', 'underdone', 'underweight'; adverbs, such as 'underfoot' and 'underground' (also a noun and an adjective); and nouns, such as 'underbelly', 'underclass', 'undercarriage', 'undergrowth', and 'underskirt'.

• Finally, there are a number of idioms in which 'below' cannot be substituted for 'under' or vice versa. For example,

under the weather, meaning 'not in good health';

under a cloud, meaning 'in disgrace or under suspicion';

under the sun, meaning 'on earth or at all' (as in 'There is nothing new under the sun' and 'Nobody under the sun works harder than you do';

to go (or come) under the hammer, meaning 'to be offered for sale at auction';

below the salt, meaning 'lowly, humble, or common';

below the belt, meaning 'against the rules, unfairly'.