The term CALL ON is composed of six words: AHOY (4 letters), SEE (3 letters), TAP (3 letters), USE (3 letters), VISIT (5 letters), and INVOKE (6 letters). AHOY is a nautical term used to hail a boat or ship, usually shouted when approaching it. To SEE is to USE one's eyes to observe something. To TAP is to lightly hit something with a finger or an object. To USE is to employ something for a purpose. To VISIT is to go to a place for a short period of time. To INVOKE is to call upon a higher power or authority for help or inspiration. Together, these words form the phrase 'call on, ' which means to ask for help or assistance.