The term 'AFTER PI LETTER' refers to the Greek alphabet, which follows the letter pi. The crossword solutions for this term are RHO (3 letters), TAU (3 letters), OMICRON (7 letters), and AREA (4 letters). Rho is the 17th letter of the Greek alphabet and is pronounced like a rolled 'r'. TAU is the 19th letter of the Greek alphabet and is pronounced like a 't'. Omicron is the 15th letter of the Greek alphabet and is pronounced like an 'o'. AREA is the 20th letter of the Greek alphabet and is pronounced like an 'a'.