What is the meaning of declination?

noun

• A condition inferior to an earlier condition; a gradual falling off from a better state.
  • synonyms: decline
• A downward slope or bend.
  • synonyms: descent, declivity, fall, decline, declension, downslope
• Astronomy) the angular distance of a celestial body north or to the south of the celestial equator; expressed in degrees; used with right ascension to specify positions on the celestial sphere.
  • synonyms: celestial latitude, dec
• A polite refusal of an invitation.
  • synonyms: regrets