The difference between Buck and Single

Buck as a noun:

A male deer, antelope, sheep, goat, rabbit, hare, and sometimes the male of other animals such as the ferret and shad.

Buck as a noun (US):

An uncastrated sheep, a ram.

Buck as a noun:

A young buck; an adventurous, impetuous, dashing, or high-spirited young man.

Buck as a noun (British, obsolete):

A fop or dandy.

Buck as a noun (US, dated, derogatory):

A black or Native American man.

Buck as a noun (US, Australia, NZ, Canada, informal):

A dollar (one hundred cents).

Buck as a noun (South Africa, informal):

A rand (currency unit).

Buck as a noun (by extension, Australia, South Africa, US, informal):

Money

Buck as a noun (US, slang):

One hundred.

Buck as a noun (dated):

An object of various types, placed on a table to indicate turn or status; such as a brass object, placed in rotation on a US Navy wardroom dining table to indicate which officer is to be served first, or an item passed around a poker table indicating the dealer or placed in the pot to remind the winner of some privilege or obligation when his or her turn to deal next comes.

Buck as a noun (US, in certain metaphors or phrases):

Blame; responsibility; scapegoating; finger-pointing.

Buck as a noun (UK, dialect):

The body of a post mill, particularly in East Anglia. See Wikipedia:Windmill machinery.

Buck as a noun (finance):

One million dollars.

Buck as a noun (informal):

A euro.

Buck as a noun:

A frame on which firewood is sawed; a sawhorse; a sawbuck.

Buck as a noun:

A wood or metal frame used by automotive customizers and restorers to assist in the shaping of sheet metal bodywork. See [http://www.hotrod.com/how-to/additional-how-to/1009sr-making-a-wood-buck/ Street Rodder "Making a Wood Buck"].

Buck as a noun (AAVE, dated, dance):

Buck as a noun:

Buck as a verb (intransitive):

To copulate, as bucks and does.

Buck as a verb (intransitive):

To bend; buckle.

Buck as a verb (intransitive, of a horse, _, or similar saddle or pack animal):

To leap upward arching its back, coming down with head low and forelegs stiff, forcefully kicking its hind legs upward, often in an attempt to dislodge or throw a rider or pack.

Buck as a verb (transitive, of a horse, _, or similar saddle or pack animal):

To throw (a rider or pack) by bucking.

Buck as a verb (transitive, military):

To subject to a mode of punishment which consists of tying the wrists together, passing the arms over the bent knees, and putting a stick across the arms and in the angle formed by the knees.

Buck as a verb (intransitive, by extension):

To resist obstinately; oppose or object strongly.

Buck as a verb (intransitive, by extension):

To move or operate in a sharp, jerking, or uneven manner.

Buck as a verb (transitive, by extension):

To overcome or shed (e.g., an impediment or expectation), in pursuit of a goal; to force a way through despite (an obstacle); to resist or proceed against.

Buck as a verb (riveting):

To press a reinforcing device (bucking bar) against (the force of a rivet) in order to absorb vibration and increase expansion. See Wikipedia: Rivet:Installation.

Buck as a verb (forestry):

To saw a felled tree into shorter lengths, as for firewood.

Buck as a verb (electronics):

To output a voltage that is lower than the input voltage. See Wikipedia: Buck converter

Buck as a noun (Scotland):

The beech tree.

Buck as a noun:

Lye or suds in which cloth is soaked in the operation of bleaching, or in which clothes are washed.

Buck as a noun:

The cloth or clothes soaked or washed.

Buck as a verb:

To soak, steep or boil in lye or suds, as part of the bleaching process.

Buck as a verb:

To wash (clothes) in lye or suds, or, in later usage, by beating them on stones in running water.

Buck as a verb (mining):

To break up or pulverize, as ores.

Single as an adjective:

Not accompanied by anything else; one in number.

Single as an adjective:

Not divided in parts.

Single as an adjective:

Designed for the use of only one.

Single as an adjective:

Performed by one person, or one on each side.

Single as an adjective:

Not married or (in modern times) not involved in a romantic relationship without being married or not dating anyone exclusively.

Single as an adjective (botany):

Having only one rank or row of petals.

Single as an adjective (obsolete):

Simple and honest; sincere, without deceit.

Single as an adjective:

Uncompounded; pure; unmixed.

Single as an adjective (obsolete):

Simple; foolish; weak; silly.

Single as a noun:

(music) A 45 RPM vinyl record with one song on side A and one on side B.

Single as a noun:

(music) A popular song released and sold (on any format) nominally on its own though usually having at least one extra track.

Single as a noun:

One who is not married.

Single as a noun (cricket):

A score of one run.

Single as a noun (baseball):

A hit in baseball where the batter advances to first base.

Single as a noun (dominoes):

A tile that has a different value (i.e. number of pips) at each end.

Single as a noun:

A bill valued at $1.

Single as a noun (UK):

A one-way ticket.

Single as a noun (Canadian football):

A score of one point, awarded when a kicked ball is dead within the non-kicking team's end zone or has exited that end zone. Officially known in the rules as a rouge.

Single as a noun (tennis, chiefly, in the plural):

A game with one player on each side, as in tennis.

Single as a noun:

One of the reeled filaments of silk, twisted without doubling to give them firmness.

Single as a noun (UK, Scotland, dialect):

A handful of gleaned grain.

Single as a verb:

To identify or select one member of a group from the others; generally used with out, either to single out or to single (something) out.

Single as a verb (baseball):

To get a hit that advances the batter exactly one base.

Single as a verb (agriculture):

To thin out.

Single as a verb (of a horse):

To take the irregular gait called singlefoot.

Single as a verb:

To sequester; to withdraw; to retire.

Single as a verb:

To take alone, or one by one.