From cruzar - to cross; the cross
A cruzada occurs any time a foot is crossed in front of or in back of the other. The lady's position at 5 of the 8 count basic (paso basico).
Also called trabada
(from batango.com (http://www.batango.com/Loomis.htm))
For me, the easiest way to understand the cruzada on the 8-count basic is that the leader walks on the open side, then when he leads the cruzada, he encourages the follower to move into his path by doing a cross.
(from tangotang.com (http://www.tangotang.com/Mambo/content/view/93/54/))
Leaders, try indicating La Cruz on the opposite side to normal, i.e., normally the leader leads the follower to cross her left foot in front of her right foot, and see what happens
(from tangocanberra.asn.au (http://www.tangocanberra.asn.au/words.htm#Cruzar))