Kamae is to be differentiated from the word tachi (立ち), used in Japanese martial arts to mean stance.
These connected mental and physical aspects of readiness may be referred to individually as kokoro-gamae (心構え) and mi-gamae (身構え), respectively.
As a further note, there are also related verbs, and adding te to the end of kamae makes the command for "get ready/in position" (構えて, kamaete).
Thus, a karate instructor ordering the students to assume a front stance might shout, "Zenkutsu dachi, kamaete!"
The basic kamae is ichimonji-no-kamae (一文字の構え), which refers to the 'straight-line' that reflects the shape of the body when adopting this position.