1. [late 17C+] (orig. UK Und., also nobb) the head; thus constr. with a to mean each, a time.
2. [late 18C–19C] (UK Und.) a hat.
3. [early 19C] in fig. use, to mean first or front.
4. [early 19C] a blow on the head.
5. [mid-19C] (UK Und.) a young boy prisoner who bullies weaker ones.
6. [mid-19C] a sovereign.
7. [mid-19C+] the penis [var. of knob n. (1c)].
8. [mid-19C; 1920s–30s] (mainly Aus.) a go, an item.
9. [late 19C–1910s] (Aus., also knob) a double-headed penny, esp. as used in the game of two-up, produced by filing down standard coins and welding them together.
10. [1970s+] a socially inept person [fig. use of sense 7].
see knob artist under knob n.
see knob-jockey under knob n.
see head rails under head n.
[mid-19C] human hair.
[late 18C–mid-19C] a wig-maker; a hat-maker.
[early 19C] (UK Und.) ingenuity.
[1900s] to keep calm.