1. arboretum   division into two classes.   eye disorder leading to partial blindness; waterfall.   plants of a region.   botanical garden where trees are studied and exhibited.   Hint Half-n-half Clue   2. friction   attrition by rubbing or disagreement.   secret code used to encrypt messages.   conjecture or logical projection beyond range.   substance producing condition of no sensation.   Half-n-half Clue   3. carat   parallelism or similarity.   unit for measuring weight of gems and purity of gold.   mutual relation.   deficiency of red blood corpuscles.   Half-n-half Clue   4. genesis   mode of formation or origin.   triangular tract of mud or sand at river's mouth.   purging of passage of body; outlet to emotion.   agent to speed up chemical reaction without it changing.   Half-n-half Clue   5. cipher   application that helps soothe or soften.   channel for fluid flow or aqueduct.   secret code used to encrypt messages.   constituent or element.   Half-n-half Clue   6. decomposition   parallelism or similarity.   floating sheet of ice.   decay; breaking into component parts.   secret code used to encrypt messages.   Half-n-half Clue   7. congruence   resemblance to remote ancestors than parents.   correspondence or harmonious relation.   device used to maintain equilibrium.   swirling motion of water or air.   Half-n-half Clue