This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. The quality or condition of being permanent; permanency.

n. The state of being permanent.

n. The reciprocal of magnetic inductance.

n. The quality or state of being permanent; continuance in the same state or place; duration; fixedness

n. The character or property of being permanent or enduring; durability; fixedness; continuance in the same state, condition, place, or office; the state of being lasting, fixed, unchanging or unchangeable in character, condition, position, office, or the like; freedom from liability to change; as, the permanence of a government or state; the permanence of liberal institutions.

n. Synonyms See lasting.

n. the property of being able to exist for an indefinite duration

"Object permanence is the concept that when we do not perceive an object, it continues to exist."

permanency   

transience    impermanence   

duration    length   

permanent   

enduringness    immortality    imperishableness    strength    durability    lastingness    perdurability    imperishingness    imperishability    sempiternity   

duration    fixedness    permanency    immovableness    fixity    fixture    constancy    durableness    lastingness   

solidity    permanency    stability    fixity    continuity    constancy    completeness    durability    uniformity    soundness