lock joint[′läk ‚jȯint]
A joint made by interlocking the joined elements, with or without other fastening.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
lock seam, lock joint
A joint or seam in sheet-metal roofing; the two edges are bent over in the form of hooks which are inserted in each other; then they are dressed down to form a seam.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.