co1 is a/the anterior (zootomy)/cranial/cephalic end (anatomy)/superior end (human anatomy) of body/object cl1; co1 (subevent) is at the starting point of long event/time-intervall cl1.
Metaphor: A tree grows in its long direction, with the roots as its starting point ( >|< |.">co'a) and the crown as its ending point ( | >< |.">co'u). Standard anatomical term to avoid ambiguity. In vertebrate usually the head, in invertebrate the end with a mouth (or equivalent structure), or the end that usually points in the direction of the organism's locomotion. See also anterior/superior absolute position (claco'uklo), anterior/superior relative position (claco'umau), posterior/inferior end (claco'u), anteroposterior (A-P) axis (selcla), ventral/anterior end (befco'u), dorsal/posterior end (tolbefco'u).