/step"up'/ , adj.
1. effecting an increase.
2. Elect. serving to increase voltage: a step-up transformer.
3. (of a lease) allowing for gradual rent increases to the highest amount permissible.
n.
4. an increase or rise in the rate or quantity of something.
Also, stepup .
[ 1890-95; adj., n. use of v. phrase step up ]