偶然ǒurán 1.事理上不一定要发生而发生的;超出一般规律的{accidental; unexpected; unusual}: ～事故{accident}|～因素{fortuitous element}|在公园里～遇见一个老同学。{run into a former classmate in the park} 2.偶尔;有时候{now and then; once in a while; sometimes}: 闹市里～也能听到几声鸟鸣。{Occasionally birds can be heard in the downtown area.}