Allow is used in both formal and informal English. Let is very common in spoken English. You allow someone to do something, but you let someone do something (without "to"):
let's used for making suggestions about what you and other people can do
let someone down to not do something that you promised to do for someone
let go of someone or something ; let someone or something go
to stop holding someone or something
let someone know
to tell someone something
let someone off to not punish someone
Something that is lethal can cause a lot of damage or death
let .ter © / irtor /
a piece of writing that one person sends to another person
( english language arts ) a sign in writing that represents a sound in a language
let•tuce / ' letas /
a plant with big green leaves that you eat cold in salads — Look
leu • ke • mi • a / lu ' kimia /
( health ) a very serious disease of the blood
lev • ee / ' levi /
( geography ) a low wall built at the side of a river to prevent a flood
leV .el 1© / 'levl/
the amount, size, or number of something
how high something is
with no part higher than another part We need level ground to play soccer on.
at the same height, standard, or position The two teams are level with 40 points each. His head is level with his mother's shoulder.
lev • er / ' levar ; ' livar /
a handle that you pull or push to make a machine work
a bar for lifting something heavy or opening something. You put one end under the thing you want to lift or open, and push the other end.
li • a • ble / ' laiabl /
responsible for paying the cost of something
be liable to do something
to be likely to do something
a person who says or writes things that are not true (called lies )
li • bel / ' laibl /
the act of printing something about someone that is not true and would give people a bad opinion of him or her
lib • er • al aw / ' libaral /
A person who is liberal lets other people do and think what they want
( politics ) supporting political and social changes to make people more equal
—ANTONYM conservative
lib • er • al arts / |libaral 'arts /