plural of cooling-off period

plural of psychological refractory period

plural of sidereal orbital period

plural of sidereal rotation period

plural of wash-up period

(chemistry) A tabular chart of the chemical elements according to their atomic numbers so that elements with similar properties are in the same group (column).

(inorganic chemistry) HIO₄ or H₅IO₆, the oxyacids of iodine in which iodine has the highest oxidation number; H₅IO₆ is a white crystalline substance (HIO₄ is not stable), and both are strong oxidizing agents.

the average interval between fertilization and birth of a mammal; ranges from 13 days for the opossum to 626 days for the Indian elephant

(astronomy) Synonym of non-periodic

(astronomy) Having an orbital period of less than 200 years, especially said of comets