[simplified from its technical meaning] n. Bits per second. Hence kilobaud or Kbaud, thousands of bits per second. The technical meaning is level transitions per second; this coincides with bps only for two-level modulation with no framing or stop bits. Most hackers are aware of these nuances but blithely ignore them.
Historical note: baud was originally a unit of telegraph signalling speed, set at one pulse per second. It was proposed at the November, 1926 conference of the Comité Consultatif International Des Communications Télégraphiques as an improvement on the then standard practice of referring to line speeds in terms of words per minute, and named for Jean Maurice Emile Baudot (1845-1903), a French engineer who did a lot of pioneering work in early teleprinters.