What does "Mazdaspeed" mean, exactly?

It's their in house performance brand name. Brand name doesn't have to mean anything as long as it has good representation what its about. Here is some history how it came about. Mazdaspeed began in 1967 as "Mazda Sports Corner", an independent racing team[2] and tuning operation run by Takayoshi Ohashi, who also ran Mazda's Tokyo distributor.[citation needed] They competed in numerous events at home and abroad, and they were also competitive at the 24 Hours of Le Mans races in the early 1980s, with the 717, 727, and 737.[citation needed] Mazda brought the racing team to Hiroshima in 1983, where the name became Mazdaspeed.[2] In 1991 Mazdaspeed's 787B won at Le Mans a feat no other Japanese team managed until Toyota did in 2018.[2] Mazdaspeed also prepared the Lantis for the JTCC between 1994-1996.