《周礼·冬官考工记·磬氏&车人》
百里见方的土地叫做同，同与同之间宽二寻、深二仞的叫做浍，浍直通河流。
匠人为沟洫，耜广五寸，二耜为耦一耦之伐，广尺深尺，谓之；田首倍之，广二尺，深二尺，谓之遂九夫为井，井间广四尺，深四尺，谓之沟方十里为成，成间广八尺，深八尺，谓之洫；方百里为同，同间广二寻，深二仞，谓之浍。专达于川，各载其名。
The land with a hundred lis as each side is called tong, and the land between two adjacent tngs with two xun wide and two ren deep is called qi, which directly connects with the river.