thematic

adj

1. Relating to or having a theme (“subject”) or a topic.

   “He had a thematic collection of postage stamps with flags on them (where (UK) thematic collection is equivalent to (US) topical collection)”

2. Relating to a melodic subject.
3. (Indo-European-studies)Of a word stem, ending in a vowel that appears in or otherwise influences the noun or verb's inflection.

   “A considerable number of derived nominals, especially thematic nouns, also exhibited o-grade roots.”

4. Of or relating to a theme (“subdivision of the Byzantine empire”).

noun

1. A postage stamp that is part of a thematic collection.
2. A case that indicates the (usually inanimate) party which is a participant to the verbal predicate where that participant does not undergo any tangible change of state.

   “The nine transrelative cases are the thematic, instrumental, absolutive, affective, stimulative, effectuative, ergative, dative, and inducive. Following are explanations of the function and usage of each case. Examples of these cases in use are provided in Sec. 4.2.10 below.”