Bail is one of several actions that the police can take after arresting you. It involves release from police custody to await a later appearance at court or a police station. Your case can be dropped while you’re on bail.
If you are bailed without charge, called ‘pre-charge bail’ this means that you will have to appear at a police station at a later date. This is so that the police can look over the evidence and decide whether or not to charge you.
Being bailed and charged, called ‘post-charge bail’ is where you have been charged and you must appear in court at a later date.
Both types can come with conditions attached which are things you must not do, for example: “You must not return to the borough of Newham” or “You must not go within 1km of an airport”