Angel
The word means messenger, and it is used of human messengers too — the job, not the species.
Both the Hebrew and the Greek word simply mean messenger, and both are used of ordinary human envoys as often as of heavenly ones; the translators decide which by context, which is why the same word is "angel" in one verse and "messenger" in the next. Appearance is rarely described and almost never winged — they are usually taken for men, which is the point of the warning about entertaining them unawares. What is described repeatedly is the reaction: the first thing they tend to say is do not be afraid.
