From Middle English attenden, atenden, from Old English ātendan, earlier ontendan (“to set on fire, set fire to, kindle, inflame, trouble, perplex”), equivalent to a- + tend. More at tend.
atend (third-person singular simple present atends, present participle atending, simple past and past participle atended)
- (transitive, obsolete) To set on fire; kindle.
- (intransitive, obsolete) To take or catch fire.