n. pl.; sing. Seneca /sing>. (Ethnol.) A tribe of Indians who formerly inhabited a part of Western New York. This tribe was the most numerous and most warlike of the Five Nations. [ 1913 Webster ]

Seneca grass(Bot.), holy grass. See under Holy. --
Seneca eil, petroleum or naphtha. --
Seneca root, or
Seneca snakeroot (Bot.), the rootstock of an American species of milkworth (Polygala Senega) having an aromatic but bitter taste. It is often used medicinally as an expectorant and diuretic, and, in large doses, as an emetic and cathartic. [ Written also Senega root, and Seneka root. ] [ 1913 Webster ]

‖n. [ L., groundsel, lit., an old man. So called in allusion to the hoary appearance of the pappus. ] (Bot.) A very large genus of composite plants including the groundsel and the golden ragwort. [ 1913 Webster ]

n. [ L. senectus aged, old age, senex old. ] Old age. [ R. ] “Senectitude, weary of its toils.” H. Miller. [ 1913 Webster ]

n. (Med.) Seneca root. [ 1913 Webster ]

n. Gum senegal. See under Gum. [ 1913 Webster ]

n. (Med. Chem.) A substance extracted from the rootstock of the Polygala Senega (Seneca root), and probably identical with polygalic acid. [ 1913 Webster ]

n. [ See Senescent. ] The state of growing old; decay by time. [ 1913 Webster ]

a. [ L. senescent, p. pr. of senescere to grow old, incho. fr. senere to be old. ] Growing old; decaying with the lapse of time. “The night was senescent.” Poe. “With too senescent air.” Lowell. [ 1913 Webster ]

n. [ OF. seneschal, LL. seniscalcus, of Teutonic origin; cf. Goth. sineigs old, skalks, OHG. scalch, AS. scealc. Cf. Senior, Marshal. ] An officer in the houses of princes and dignitaries, in the Middle Ages, who had the superintendence of feasts and domestic ceremonies; a steward. Sometimes the seneschal had the dispensing of justice, and was given high military commands. [ 1913 Webster ]

Then marshaled feast
Served up in hall with sewers and seneschale. Milton. [ 1913 Webster ]

Philip Augustus, by a famous ordinance in 1190, first established royal courts of justice, held by the officers called baitiffs, or seneschals, who acted as the king's lieutenants in his demains. Hallam. [ 1913 Webster ]

n. The office, dignity, or jurisdiction of a seneschal. [ 1913 Webster ]