Meaning verification: In general acknowledgment stands for statement declaring something to be factual or true and cetified by an authority. In other words acknowledgemnt confirms that somethis is genuine.
Furthemore in business acknowledgment is used in communiaction between buyer and seller. In this meaning sending acknowledgment means that seller has accepted buyers order.
Legal meaning of acknowledgemt stands for formal declaration made under oath, or in the presence of a notary public or other competent authority.