cog·i·tate 
(kŏjĭ-tāt′)
(kŏjĭ-tāt′)intr. & tr.v. cog·i·tat·ed, cog·i·tat·ing, cog·i·tates
To take careful thought or think carefully about; ponder. See Synonyms at think.
[Latin cōgitāre, cōgitāt- : co-, intensive pref.; see CO- + agitāre, to consider; see AGITATE.]
cogi·ta′tor n.