per·i·clase 
(pĕrĭ-klās′, -klāz′)
(pĕrĭ-klās′, -klāz′)n.
A mineral form of magnesium oxide, MgO, usually occurring in cubic crystals or grains.
[German Periklas : Greek peri-, intensive pref.; see PERI- + Greek klasis, breaking (from its perfect cleavage); see ORTHOCLASE.]
- intracellular
- intracellularly
- intracerebral
- intracerebrally
- in tracks
- Intracoastal Waterway
- intracompany
- intracranial
- intracranially
- intractability
- intractable
- intractableness
- intractably
- intracutaneous
- intracutaneously
- intracytoplasmic
- intraday
- intradermal
- intradermally
- intradermal test
- intrados
- intrafallopian
- intragalactic
- intramolecular
- intramolecularly