1. The act of assuming, or taking to or upon one's self; the act of taking up or adopting. The assumption of authority. (Whewell)
2. The act of taking for granted, or supposing a thing without proof; supposition; unwarrantable claim. This gives no sanction to the unwarrantable assumption that the soul sleeps from the period of death to the resurrection of the body. (Thodey) That calm assumption of the virtues. (W. Black)
3. The thing supposed; a postulate, or proposition assumed; a supposition. Hold! says the Stoic; your assumptions wrong. (Dryden)
4. (Science: logic) The minor or second proposition in a categorical syllogism.
5. The taking of a person up into heaven. Hence: a festival in honor of the ascent of the virgin Mary into heaven.
Origin: oe. Assumpcioun a taking up into heaven, L. Assumptio a taking, fr. Assumere: cf. F. Assomption. See Assume.