Definitions of acknowledge:

• verb:   accept (someone) to be what is claimed or accept his power and authority

  Example: "The Crown Prince was acknowledged as the true heir to the throne"

• verb:   accept as legally binding and valid

  Example: "Acknowledge the deed"

• verb:   express obligation, thanks, or gratitude for

  Example: "We must acknowledge the kindness she showed towards us"

• verb:   report the receipt of

  Example: "The program committee acknowledged the submission of the authors of the paper"

• verb:   declare to be true or admit the existence or reality or truth of

  Example: "She acknowledged that she might have forgotten"

• verb:   express recognition of the presence or existence of, or acquaintance with

  Example: "He never acknowledges his colleagues when they run into him in the hallway"