independently; alone; by oneself; single-handedly
Used when someone does something without help, or when something is done separately from others. Often implies acting on one's own initiative or without assistance.
彼は単独でその問題を解決した。
He solved the problem by himself.
この装置は単独で動作します。
This device operates independently.
Compound of 単独 (tandoku, 'sole, single') + the particle で (de, indicating manner or means).