in your thoughts
- within the brain in thought or meditation intellectually in idea
- inside mind; in thought or meditation; intellectually; in concept.
1660s, from psychological + -ly (2).
(adv.) Within the head; in thought or meditation; intellectually; in concept.
He mentally constructed a system of universal law; and, when, at the end of his captivity, he accompanied his pupils, the sons of Coyet, to the university, of Leiden, he was enabled to publish, in 1661, the fruits of his reflections under the title of Elementa jurisprudentiae universalis, libri duo.