- "To keep an ... on" means to watch closely - Anatomical term for “ball-in-socket” - Behold - Central spot - Centre of a cyclone - Centre of storm - Cyclone centre
- Darker part of a sunspot - Shade - Shadow - Shadow cast during an eclipse - The conical shadow projected from a planet or satellite, on
the side opposite to the sun, within which a spectator could see no
portion of the sun's disk; -- used in contradistinction from penumbra.
See Penumbra. - The central dark portion, or nucleus, of a sun spot. - The fainter part of a sun spot; -- now more commonly called
penumbra.
- Arm bones - Circle measurements of arm bones - Diameter halves - Half-diameters - Lines frorn centre to circumference - Lines joining the centre of a circle to its circumference - Spokes