An older male, who has a younger lover, generally considerably younger, though not always the case.
Mainly an older man who takes on the role of being a father, as well as lover in a relationship.
This can include the trading of gifts, cash, and such in exchange for sexual intimacy. It comes close to the lines of Prostitution, in those instances, though it is an ancient form of homosexuality, as practices by Ancient Greeks.
Known as Pederasty.
It is not just about Money though, it can be also where the older male provides safe sanctuary to the younger male, provides other amenities, including lavish gifts, as signs of affection.
There are several connotations for the term.
In the BDSM culture / community it can refer to the dominating partner, who also is inclined to not always provide full discipline, but will let some issues slide. Hence the term Daddy.
It is also about role playing in the culture, as well as true affection. In that while the 'daddy' disciplines the 'child' it is done out of love, based on the standard 'parent/child' relationship. This does not mean that the 'child' in this instance is actually a minor, and that there is no consensual agreement. The exact opposite is true, in that it IS CONSENSUAL, and the 'child' is merely role playing, and is of legal age.
They are also older, but the differences may not be that great.
Various forms are of what is termed being a daddy today, was part of Ancient Greek Culture, where an older man was expected to show the younger members the duties expected of an adult, which included sexual relations. (see Pederasty)
No set practice exists, other than a term used to describe the senior member of a relationship, where the younger one is more than a few years younger.
Can be derogatory to either party as well, as in implying that one is involved with the other, strictly for the fringe benefits of such a relationship. That being the gifts, but also the care.
Usually a 'daddy' is the authoritive figure in the relationship as well, who is the one responsible for the major decisions within the relationship. Not always the case, but generally perceived as such.
Practice (Associated Acts): Used as a term of affection, from a younger male to the older male, or in the case of a wife to a husband, or girlfriend to boyfriend. Age separation not always being applicable to use of the term.
More of a saying, to show appreciation.
Also used to describe a relationship between a younger person, who would normally not be involved with the older person, if not for the gifts, security, cash being doled out. This generally is noted as the older person being one's 'sugar daddy' or 'provider'.
Noteworthy: Depending on the age disparity, if extreme, one is usually referred to as a Sugar Daddy, mostly noted in young women with older rich men. However, older men with Twink aged boyfriends, are also referred to as being sugar daddies.
Daddy Sauce is a term used to describe the semen from an older man, and can be used in a negative sense.
The obvious one, is father, male parent of a child.