IPA: /ˌaɪsəˈmɛrɪk/
KK: /ˈaɪsəˌmɛrɪk/
Relating to or having the same molecular formula but different structural arrangements of atoms.
The two compounds are isomeric, meaning they have the same chemical formula but different structures.
Isomeric → It is formed from "iso-" (meaning equal) and "meros" (meaning part). The word "isomeric" refers to compounds that have the same molecular formula but different structural arrangements, hence they are equal in composition but different in structure.
Think of 'equal parts' ('iso-') that are arranged differently ('meros') — that's what isomeric means.