To preach, to berate, to scold.
To teach (somebody) by giving a speech on a given topic.
a class that primarily consists of a (weekly or other regularly held) lecture (as in sense 1)
A berating or scolding.
A spoken lesson or exposition, usually delivered to a group.
To keep safe; to defend; to guard; to prevent harm coming to.
To book a passenger on a later flight if there is a chance they will not be able to board their earlier reserved flight.