Green’s Dictionary of Slang

beat n.1

[SE beat the bounds; note a police beat is SE]

1. [late 18C+] (orig. UK Und.) a street or streets as walked by a prostitute.

2. [early 19C+] (orig. UK Und.) one’s own area of activity, operation.

3. [mid-19C] (UK Und.) an area in which a pickpocket works.

4. [mid-19C] (UK Und.) the area patrolled by a watchman.

5. [1900s–60s] (US prison) that area in which a criminal gang operates, thanks to bribing a local politician/police department.

6. [1930s] an area where drugs are sold on the street.

7. [1940s+] (Aus.) the area patrolled by a sheep or cattle musterer.

In phrases

bash the beat (v.) (also do the beat)

[1970s+] (Aus. gay) to frequent an area in search of a sexual partner.

off one’s beat (also off the beat)

[1900s–10s] (mainly Aus.) drifting away from the subject in hand, out of one’s usual routine.

SE in slang uses

In compounds

beat basher (n.)

[1950s] (UK juv.) a police officer.

beat pounder (v.)

[1940s+] a policeman.