Until is a commonly used word in sentences to indicate the limit or endpoint of a particular action or period. However, there are other synonyms that can be used to convey similar meanings, such as 'till', 'up to', 'before', 'as far as', 'as long as', and 'while'. 'Till' is often used interchangeably with 'until', whereas 'up to' implies that something reaches a particular point or level. 'Before' is used to indicate the endpoint of a particular event. 'As far as' indicates the extent of something, while 'as long as' suggests that something continues for a specific duration. 'While' is a synonym for 'until' that can be used to indicate that something is in progress or continuing during a particular period.