The Old Testament, written primarily in Hebrew, uses the word mal’ak (pronounced mal-AHK) for angel. Its basic meaning is “messenger, one who is sent.” This word occurs more than two hundred times in the Old Testament, and it can refer to either human or heavenly messengers. The New Testament uses the Greek word angelos (pronounced AN-gel-os), and it also occurs nearly two hundred times. It, too, can refer to either a human or a supernatural messenger. 

We commonly use the word angel to describe any kind of heavenly supernatural being apart from God Himself. The reality is a bit more complex since the Bible gives us glimpses of various spiritual beings, including cherubim, seraphim, archangels, principalities, and powers.

Nevertheless, the word angel reassures us that God wants to communicate with us, and He has many ways of sending us messages and messengers. His greatest communication is in His written Word, the Bible, and His Incarnate Word, the Son. Praise God today that He exists and He is not silent.

[Angels] come to attend the redeemed; they wait on their steps; they sustain them in trial; they accompany them when departing to heaven. 
Albert Barnes