Circularize comes from circular (a printed notice sent to many people) + -ize, from Latin circularis, from circulus ('small ring'), diminutive of circus ('ring'). The historical trail runs through circulus in Latin and circus in Latin. Morphologically, circularize is transparent: it draws on circular (a printed notice sent to many people) + -ize, from Latin circularis, from circulus ('small ring'), diminutive of circus ('ring'). Used as a verb, circularize now means "distribute circulars or notices to a group of people", so the present definition can be read against the older forms and meanings. The same lexical family is also visible in derived forms such as circularization and related forms such as circular, circulate, and circle. The result is a borrowed or transmitted form whose modern spelling carries a compact record of its route into English.