11-letter words that end in ium
- phosphonium — the positively charged group PH 4 + .
- planetarium — an apparatus or model representing the planetary system.
- polychasium — a form of cymose inflorescence in which each axis produces more than two lateral axes.
- polyzoarium — a bryozoan colony, or its supporting skeleton.
- ponzimonium — theoretical financial turmoil in the wake of uncovering suspected Ponzi schemes
- positronium — a short-lived atomic system consisting of a positron and an electron bound together.
- postscenium — a wing on either side of the stage of an ancient Greek or Roman theatre where props could be stored and actors could prepare; a parascenium
- promycelium — a short filament produced in the germination of a spore that bears small spores and then dies.
- prothallium — Botany. the gametophyte of ferns and related plants.
- pteropodium — the foot of a pteropod.
- quadrennium — a period of four years.
- radiocesium — cesium 137.
- radiosodium — the radioactive isotope of sodium having an atomic mass of 24 and a half-life of 14.9 hours: used as a tracer in biochemistry.
- roentgenium — a superheavy, synthetic radioactive element with a very short half-life. Symbol: Rg; atomic number: 111.
- satellitium — a group of three or more planets lying in one sign of the zodiac
- scriptorium — a room, as in a monastery, library, or other institution, where manuscripts are stored, read, or copied.
- sericterium — a silk-producing gland in a silkworm
- sphaeridium — a round body found on sea urchins
- sporogonium — the sporangium of mosses and liverworts.
- staminodium — a sterile or abortive stamen.
- stylopodium — a glandular disk or expansion surmounting the ovary and supporting the styles in plants of the parsley family.
- subdelirium — a mild delirium with lucid intervals.
- supercilium — the fillet above the cyma of a cornice.
- syllabarium — syllabary.
- taurobolium — the sacrifice of a bull, followed by the baptism of neophytes in the blood, as practiced in the ancient rites of Mithras or Cybele.
- telescopium — an inconspicuous constellation in the S hemisphere, close to Sagittarius and Ara
- termitarium — a termites' nest.
- tetrazolium — a derivative of an acidic chemical compound
- tridominium — the shared rule of three states
- unnilennium — meitnerium.
- unnilhexium — seaborgium.
- unniloctium — hassium.
- ununpentium — a superheavy, synthetic, radioactive element with a short half-life. Symbol: Uup; atomic number: 115.
- ununquadium — a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Fl; atomic number: 114.
- ununseptium — a superheavy, synthetic, radioactive element with a short half-life. Symbol: Uus; atomic number: 117.
- xenodochium — a guesthouse for receiving strangers
- zoogonidium — a motile plant or fungal structure containing spores