Merriam-Webster Collegiate Dictionary - understand

 verb  (understood; -standing)  Etymology: Middle English, from Old English ~an, from under + standan to stand  Date: before 12th century  transitive verb  1.  a. to grasp the meaning of ~ Russian  b. to grasp the reasonableness of his behavior is hard to ~  c. to have thorough or technical acquaintance with or expertness in the practice of ~ finance  d. to be thoroughly familiar with the character and propensities of ~s children  2. to accept as a fact or truth or regard as plausible without utter certainty we ~ that he is returning from abroad  3. to interpret in one of a number of possible ways  4. to supply in thought as though expressed “to be married” is commonly understood after the word engaged  intransitive verb  1. to have ~ing ; have the power of comprehension  2. to achieve a grasp of the nature, significance, or explanation of something  3. to believe or infer something to be the case  4. to show a sympathetic or tolerant attitude toward something  • ~ability noun  • ~able adjective Synonyms:  ~, comprehend, appreciate mean to have a clear or complete idea of. ~ and comprehend are very often interchangeable. ~ may, however, stress the fact of having attained a firm mental grasp of something orders that were fully understood and promptly obeyed. comprehend may stress the process of coming to grips with something intellectually I have trouble comprehending your reasons for doing this. appreciate implies a just evaluation or judgment of a thing's value or nature failed to appreciate the risks involved.