spell: English has three distinct words spell, although two of them come from the same ultimate source. Spell ‘name the letters of a word’ [13] was adapted from Old French espeler ‘read out’. This was descended from an earlier *espeldre, which was borrowed from prehistoric Germanic *spellōn. And it was a noun relative of this, *spellam, which gave English spell ‘magic formula’ [OE]. Spell ‘period of time’ [16] may go back ultimately to Old English spelian ‘substitute’; its original meaning was ‘replace someone else at a job’, and the main modern sense ‘period of time’ did not emerge, via ‘period of work’, until the 18th century.
