Merriam-Webster Collegiate Dictionary - observe

 verb  (~d; observing)  Etymology: Middle English, from Anglo-French ~r, from Latin observare to guard, watch, ~, from ob- in the way, toward + servare to keep — more at conserve  Date: 14th century  transitive verb  1. to conform one's action or practice to (as a law, rite, or condition) ; comply with  2. to inspect or take note of as an augury, omen, or presage  3. to celebrate or solemnize (as a ceremony or festival) in a customary or accepted way  4.  a. to watch carefully especially with attention to details or behavior for the purpose of arriving at a judgment  b. to make a scientific observation on or of  5. to come to realize or know especially through consideration of noted facts  6. to utter as a remark  intransitive verb  1.  a. to take notice  b. to make observations ; watch  2. remark, comment  Synonyms: see keep  • observingly adverb