del·ti·ol·o·gy 
(dĕl′tē-ŏlə-jē)
(dĕl′tē-ŏlə-jē)n.
The collection and study of postcards.
[From Greek deltion, diminutive of deltos, writing tablet, letter.]
del′ti·olo·gist n.
- heterophonic
- heterophony
- heterophyllous
- heterophylly
- heteroplastic
- heteroplasty
- heteroploid
- heteroploidy
- heteropteran
- heteropterous
- heterosexism
- heterosexist
- heterosexual
- heterosexuality
- heterosis
- heterosporous
- heterospory
- heterostyled
- heterostylous
- heterostyly
- heterotaxia
- heterotaxic
- heterotaxy
- heterothallic
- heterothallism