English
explainer
From explain + -er.
A compound of explain + -er
Latin plānus ‘level, plain’
Latin plānō ‘to flatten’
Latin explānō ‘to make plain, explain’
Old French explaner
Middle English explanen
English explain
Today it means
noun A guide that explains a topic.
Language periods are conventional ranges, not dates for this word.
Etymograph / explainer