19. (Mach.)

Defn: The proper relative position or adjustment of parts, not as to design or proportion, but with reference to smooth working; as, the engine is in line or out of line or out of line.

20. The track and roadbed of a railway; railroad.

21. (Mil.) (a) A row of men who are abreast of one another, whether side by side or some distance apart; — opposed to column. (b) The regular infantry of an army, as distinguished from militia, guards, volunteer corps, cavalry, artillery, etc.

22. (Fort.) (a) A trench or rampart. (b) pl.

Defn: Dispositions made to cover extended positions, and presenting a front in but one direction to an enemy.

23. pl. (Shipbuilding)

Defn: form of a vessel as shown by the outlines of vertical, horizontal, and obique sections.

24. (Mus.)

Defn: One of the straight horizontal and parallel prolonged strokes on and between which the notes are placed.