the GNU version of the Collaborative International Dictionary of English
n. One who contemplates.
The Century Dictionary and Cyclopedia
n. One who engages in contemplation or reflection; one who meditates or studies. One who merely observes affairs, without taking part in them.
Word Usage
"There will not even be memory of the personality; no thought that the contemplator is the self — Socrates, for example — or that it is Intellect or Soul."