Bal"last (?), n. [D. ballast; akin to Dan. baglast, ballast, OSw. barlast, Sw. ballast. The first part is perh. the same word as E. bare, adj.; the second is last a burden, and hence the meaning a bare, or mere, load. See Bare, a., and Last load.]
1. Naut.
Any heavy substance, as stone, iron, etc., put into the hold to sink a vessel in the water to such a depth as to prevent capsizing.
2.
Any heavy matter put into the car of a balloon to give it steadiness.
3.
Gravel, broken stone, etc., laid in the bed of a railroad to make it firm and solid.
4.
The larger solids, as broken stone or gravel, used in making concrete.
5.
Fig.: That which gives, or helps to maintain, uprightness, steadiness, and security.
It [piety] is the right ballast of prosperity.
Barrow.
Ballast engine, a steam engine used in excavating and for digging and raising stones and gravel for ballast. -- Ship in ballast, a ship carring only ballast.
© Webster 1913.
Bal"last, v. t. [imp. & p. p. Ballasted; p. pr. & vb. n. Ballasting.]
1.
To steady, as a vessel, by putting heavy substances in the hold.
2.
To fill in, as the bed of a railroad, with gravel, stone, etc., in order to make it firm and solid.
3.
To keep steady; to steady, morally.
'T is charity must ballast the heart.
Hammond.
© Webster 1913.