Where does “MgH” come from?

MgH (Translingual) comes from German MG, from Translingual g, from English gaseous, from English -eous, from English -ous, from Middle English -ous, from Old French -us, from Latin -ōsus.

Ancestry of “MgH”, step by step

MgH traces back through two separate lines of ancestry.

via German MG

StepLanguageWordMeaning
1GermanMGInitialism of Maschinengewehr
2Translingualg
3EnglishgaseousRelating to, or existing as, gas; Of a liquid...
4English-eous"Used with nouns to form adjectives with the...
5English-ousUsed to form adjectives from nouns, to denote...
6Middle English-ous
7Old French-us-ous, used for forming adjectives
8Latin-ōsusose, -ous, -ful (full of or overly prone to)
9Old Latin-ōssus

via Translingual H

StepLanguageWordMeaning
1TranslingualHhydrogen
2Etruscan𐌇
3Ancient GreekηLower-case eta, the seventh letter of the ancient Greek alphabet. Its name was ἦτα and it represented a long open-mid front unrounded vowel:. It is often transliterated as either e or i. It is preceded by ζ and followed by θ
4Phoenician𐤇het; heth
5Egyptian?
Every word from Old Latin -ōssus