'bacillariophyta' originates from New Latin, combining the genus name 'Bacillaria' (used for a group of diatoms) and the Greek-derived suffix 'phyta' (from Greek 'phyton') meaning 'plant'.

'bacillariophyta' developed as a modern taxonomic name from earlier terms for the same organisms such as 'Diatomeae' or the class name 'Bacillariophyceae', eventually standardizing as the phylum-level name 'Bacillariophyta' in botanical/zoological usage.

Initially these organisms were broadly described as 'plantlike algae'; over time the term has come to denote specifically the phylum of diatoms with silica cell walls.