The term 'on the mark' is an idiom that means to be ACCURATE or precise. This phrase is often used in sports, such as archery, where hitting the target is essential. The crossword solutions for this term are ACCURATE (8 letters), APT (3 letters), TRUE (4 letters), and SPANG (5 letters). ACCURATE means exact or precise, APT means suitable or appropriate, TRUE means ACCURATE or correct, and SPANG means to hit the target exactly. All of these words can be used to describe the phrase 'on the mark'.