函	451A30   31.21	部居	畫數  8	ㄏㄢˊ [han2] .
N	(1)  (AC) protective armorplate, breastplate. (2)  A case, shield: 劍函 scabbard, 鏡函 dressing case containing mirror. (3)  Letter of correspondence: 來函 your (“incoming”) letter; 公函 official letter; 函請，函邀 invite by letter; 函授 [han2shou4]↓.
V	Var. of 涵 63A.21 and 含 81.40.
Words	1.函洞 [han2dong4], n., railway tunnel.  2.函丈 [han2zhang4], n., (court. salutation in letter to) teacher.  3.函件 [han2jian4], n., correspondence, mail, letters.  4.函授 [han2shou4], n., as in 函授學校 correspondence school.  5.函數 [han2shu4], n., (math.) function.