Used as a suffix after a number or quantity to mean 'less than that amount', not including the stated number. Often contrasted with 以下 (or less, including the number). Can also be used as a noun or adverb.
18
歳
未満
の
方
は
ご
利
用
いただけ
ませ
ん
。
Those under 18 years of age cannot use this service.
