In this wiktionary page https://en.m.wiktionary.org/wiki/厚 the etymology for the kanji 厚 is not complete: they wrote that it's an ideogrammic compound but they didn't write the component functions. I want to know the etymology for this kanji (and also if someone can complete this page in wiktionary to help learners it would be great).
2 Answers
「[厚]{こう}」(thick, large, deep, strong) is comprised of semantic「厂」(cliff) and simultaneously semantic and phonetic「[𣆪]{こう}」(salt container shaped with a wide mouth and narrow neck > thick, strong flavour of salt). The character「厚」was originally used to describe the wideness and deepness of lofty hills and mountains.
「𣆪」was a character that fell into disuse very early on. As part of「厚」,「𣆪」was later graphically corrupted into「⿱日子」, so「⿱日子・㫗」is now interpreted as a variant form of「厚」.
商
甲
佚211
合集34124春秋
金
魯伯厚父盤
集成10086
篆
說文解字
東漢
隸
婁壽碑
今
楷
Note,「厚」and「𣆪」originally represented the same word; the different kanji gave the different nuances.
For reference, glyph evolution of「𣆪」, which depicts a vessel used for storing salt, shaped with a wide opening and a narrow neck:
商
甲
後2.32.11
合集18637商
金
冊丁酉爵
集成8791
篆
說文解字
今
楷
Reference
- 季旭昇《說文新證》
This is a what I found in 成り立ちで知る漢字のおもしろ世界: 道具・家・まち編 (by 伊東信夫). Translation is by me, so might not be perfect, but here it goes:
「厚」is formed of 「厂」(がんだれ、cliff radical)、「子」and 「日」, the last two being combined.
Although 「厂」usually means ''cliff'' (in fact being the bare minimum version of 「崖」), it here has the same meaning as 「宀」(ベン), namely "the mausoleum in which the spirits of the ancestors (祖霊、それい) are enshrined". The combination of 「日」and 「子」symbolizes the alcohol offered to the ancestors during the ceremony, hence meaning "offering to the gods/ancestors".
Therefore, 「厚」means honoring the ancestors in a 手厚い (the translation I found is "warm, courteous", I would say that the nuance here is "to carefully attend to", "with attention to details") way. It is thought that from this meaning, 「厚」evolved to mean「物の厚み」i.e. the thickness, profoundness of things.
Edit: looks like the above book is available on google books