'Bacillariaceae' originates from New Latin (scientific Latin), formed from the genus name 'Bacillaria' plus the family suffix '-aceae'; 'Bacillaria' itself is derived from Latin 'bacillus' meaning 'little rod'.

'Bacillariaceae' was created in modern scientific (New) Latin as a family name based on the genus 'Bacillaria' (itself Latinized from 'bacillus'), and has been used in biological taxonomy since the development of modern classification systems in the 19th century.

Originally the root referred to 'little rod' (shape-based term), and over time the term became the formal name for a taxonomic family of diatoms rather than a descriptive phrase about shape.