Thirdly

adjective
1.
next after the second; being the ordinal number for three.
2.
being one of three equal parts.
3.
Automotive. of, relating to, or operating at the gear transmission ratio at which the drive shaft speed is greater than that of second gear for a given engine crankshaft speed, but not as great as that of fourth gear, if such exists:
third gear.
4.
rated, graded, or ranked one level below the second:
He’s third engineer on the ship.
noun
5.
a third part, especially of one (1/3).
6.
the third member of a series.
7.
Automotive. third gear:
Don’t try to start a car when it’s in third.
8.
a person or thing next after second in rank, precedence, order:
The writer of the best essay will receive a gold medal, the second a silver, and the third a bronze.
9.
Usually, thirds. Law.

the third part of the personal property of a deceased husband, which in certain circumstances goes absolutely to the widow.
a widow’s dower.

10.
Music.

a tone on the third degree from a given tone (counted as the first).
the interval between such tones.
the harmonic combination of such tones.

11.
Baseball. third base.
12.
Usually, thirds. Commerce. a product or goods below second quality.
Compare first (def 17), second1 (def 23).
adverb
13.
in the third place; thirdly.
adjective (usually prenominal)
1.

coming after the second and preceding the fourth in numbering or counting order, position, time, etc; being the ordinal number of three: often written 3rd
(as noun): he arrives on the third, the third got a prize

2.
rated, graded, or ranked below the second level
3.
denoting the third from lowest forward ratio of a gearbox in a motor vehicle
noun
4.

one of three equal or nearly equal parts of an object, quantity, etc
(as modifier): a third part

5.
the fraction equal to one divided by three (1/3)
6.
the forward ratio above second of a gearbox in a motor vehicle. In some vehicles it is the top gear
7.

the interval between one note and another three notes away from it counting inclusively along the diatonic scale
one of two notes constituting such an interval in relation to the other See also interval (sense 5), major (sense 15), minor (sense 4d)

8.
(Brit) an honours degree of the third and usually the lowest class Full term third class honours degree
9.
(pl) goods of a standard lower than that of seconds
adverb
10.
Also thirdly. in the third place
sentence connector
11.
Also thirdly. as the third point: linking what follows with the previous statements as in a speech or argument

third (thûrd)
adj.

Coming next after second, as in order, rank, or time.

Being the digit that is adjacent to and is on the outermost side of the second digit, as on a foot.

third n.