十月 literally means 'ten month' and is the standard Mandarin term for the tenth month of the Gregorian calendar — October. The character 十 (shí) means 'ten', and 月 (yuè) means 'month'; together, they form a compound noun following the common Chinese pattern of numeral + measure word (here, 月 functions as both measure word and lexical noun). Unlike English, Chinese months are always expressed this way — no standalone names like 'October' exist in native vocabulary.

This term appears frequently in dates, seasonal descriptions, holidays (e.g., National Day on October 1st), and academic or business contexts (e.g., school terms, fiscal periods). It’s neutral in register — appropriate for formal reports, casual conversation, and written notices. Note that 十月 is never used alone to mean 'ten months' (a duration); for that meaning, you’d say 十个月 (shí gè yuè), where 个 is the required generic measure word.