'spelt' (noun) originates from Old English, specifically the word 'spelt', where the root meant 'a type of grain'. 'Spelt' (verb, as the past form of 'spell') is derived from Old English 'spell'/'spellan' (to tell or relate), via Middle English forms.

'spelt' (noun) developed from Proto-Germanic roots (cf. Old English 'spelt') and remained in English as 'spelt'. The verb sense comes from Old English 'spellan', became Middle English 'spellen', and gave modern 'spell' with past forms including 'spelt' and the variant 'spelled'.

For the noun, it initially meant 'a particular kind of grain' and has retained that meaning. For the verb-derived form, it originally related to 'telling' or 'narrating' and later specialized to naming or forming letters of words; the past form 'spelt' preserves that grammatical function.