As a Noun:
1. The condition of a man's penis when he is sexually excited and his penis is stiff, swollen, and sticking up. English = erection.
As a Verb or Adjective:
1. Of a penis, to become stiff, swollen, and sticking up. English = become erect.
2. Of a man, to become sexually excited so that his penis becomes erect. English = get an erection.