The aim of this study is to focus on the verbal stimuli of the Vocabulary subtest of the Wechsler Adult Intelligence Scale -- Fourth Edition (WAIS-IV). To our knowledge, this is the first research to examine whether the abstractness/concreteness and the lexical category of the words in the WAIS-IV vocabulary subtest influence the ability to explain their meaning. In the first step, we collected ratings of the degree of abstractness/concreteness and the lexical category of the 27 verbal stimuli of vocabulary subtest. From the second step, the results showed that the ability to explain the meaning of words for 497 participants (aged 19-89) was better with concrete concepts than with abstract ones; and the concreteness effect, i.e., the advantage in the processing of the concrete over the abstract terms, does not disappear with age. More specifically, the ability to define the abstract words does not decline with age. Still, this ability is maintained likely because linguistic knowledge is preserved in healthy elderly. Besides, the correctness in defining nouns is always superior to that in defining adjectives and verbs across all age groups. The nouns are defined more correctly than adjectives in the all age groups. The verbs are defined more correctly than adjectives in the all age groups except for the groups over 60 years of age, although at 80-89 years of age the verbs are statistically more difficult to define than adjectives.