आध्यैādhyai1 P. To think on, meditate, remember.
1 Parasmaipada To think on, meditate, remember.
कोशःDictionaries
V. S. Apte, The Practical Sanskrit–English Dictionary. Look up any word of the Gita in Devanagari, IAST or Harvard-Kyoto, or browse the headwords letter by letter.