Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Wikipedia.
Related to apparent horizon: visible horizon
apparent horizon[ə′pa·rənt hə′rīz·ən]
The boundary of a region in space-time in which the gravitational field is so strong that the cross-sectional area of an outgoing light pulse decreases.
The visible line of demarcation between land or the sea and the sky.