拱点（apsis，复数为apsides）在天文学上的意义是在椭圆轨道上运行的天体最接近或最远离它的引力中心，通常也就是系统的质量中心的点。

最靠近引力中心的点称为近拱点（periapsis）或近心点（pericentre ），而距离最远的点就称为远拱点（apoapsis ）或远心点（apocentre ）。连接近拱点和远拱点的直线称为拱点线，是椭圆的长轴，也是椭圆内最长的直线段。

连接近拱点与远拱点的直线称为拱点线。椭圆的长轴与拱点线同线。

以下是用于辨识椭圆轨道的项目：

An apsis (Greek:ἁψίς; plural apsides /ˈæpsᵻdiːz/, Greek: ἁψίδες) is an extreme point in an object's orbit. The word comes via Latin from Greek and is cognate with apse. For elliptic orbits about a larger body, there are two apsides, named with the prefixes peri- (fromπερί (peri), meaning "near") and ap-, or apo- (fromἀπ(ό) (ap(ó)), meaning "away from") added to a reference to the thing being orbited.