The character "哪儿" is formed through a combination of the core interrogative character 哪 (nǎ), which means "which", and the colloquial, retroflex suffix 儿 (er). The "儿" suffix, originating from northern Mandarin dialects (particularly Beijing dialect), is fused onto the end of the character not as a separate written syllable in standard pinyin for this word, but as a phonological alteration that modifies the pronunciation of the preceding syllable "nǎ" to "nár", thereby creating a single, merged spoken unit. This fusion creates a familiar, informal version of the question word meaning "where".