Definition:

All the time; always available; without a break.

Example:

1) In New York City, a lot of stores are open 24/7.

2) I had to move because my neighbors played loud dance music 24/7.

Etymology:

Some convenience stores are open 24 hours a day, 7 days a week. The phrase is used for anything that is always (or nearly always) available.

Synonyms:

around the clock