The only free and comprehensive online etymological dictionary of the Spanish language
magno (Adjective) "great"
Borrowed fom Latin magnus 'id.' From Proto-Italic *magno- 'id.' From Proto-Indo-European *m̥ǵ-no- 'id.' From the root *meǵh2- "much."
Also the origin of the surname Magnet.
Indo-European
Romance
Portuguese magno, Italian magno
Celtic
Gaulish Magios (name) "great," Middle Irish maige "large"
Germanic
Gothic mikils "large," Old Norse mikill 'id.,' Old High German mihhil 'id.,' Old Saxon mikil 'id.,' Old English micel 'id.' (Middle English muchel, English much)
Albanian
Albanian madh "large"
Hellenic
Ancient Greek μέγας (mégas) "large"
Armenian
Armenian mec "large"
Indo-Iranian
Sanskrit máhi- "large," Avestan mazōi "big"
Tocharian
A māk "many," B māka 'id.'