the act or the faculty of observing or taking notice; the act of seeing, or of fixing the mind upon, anything.-the result of an act, or of acts, of observing; view; reflection; conclusion; judgment.-hence: an expression of an opinion or judgment upon what one has observed; a remark.-performance of what is prescribed; adherence in practice; observance.-the act of recognizing and noting some fact or occurrence in nature, as an aurora, a corona, or the structure of an animal.-specifically, the act of measuring, with suitable instruments, some magnitude, as the time of an occultation, with a clock; the right ascension of a star, with a transit instrument and clock; the sun's altitude, or the distance of the moon from a star, with a sextant; the temperature, with a thermometer, etc. -the information so acquired.