voluntary [LME] Voluntary goes back to Latin voluntas ‘will’. The related word volunteer dates from the late 16th century as a military term.
英语词源词典收录了6069条英语词源词条，基本涵盖了全部常用英语词汇的起源、历史，是研究英语词汇或通过词源学英语的必备工具。