The story
The table is termed “periodic” because it follows the periodic law – when chemical elements are arranged in order of increasing atomic number, elements with similar properties recur at intervals.
Etymology from Wiktionary, CC BY-SA 4.0.
periodic table
pe·ri·od·ic ta·bleToday it means: A tabular chart of the chemical elements according to their atomic numbers so that elements with similar properties are in the same group (column). Full definition →