Webster's Revised Unabridged Dictionary · 1913

Cantar

Cantar , noun

[Italian cantaro (in sense 1), Sp. cantaro (in sense 2).]

1.
A weight used in southern Europe and East for heavy articles. It varies in different localities; thus, at Rome it is nearly 75 pounds, in Sardinia nearly 94 pounds, in Cairo it is 95 pounds, in Syria about 503 pounds.
2.
A liquid measure in Spain, ranging from two and a half to four gallons. — Simmonds

Also: Cantarro