Colloquial Beijing/northern speech.
半 +
儿化 (érhuà) = bànr — same meaning as plain
半 'half', but warmer and more spoken-feeling. Often appears in
一半儿 (yí bànr, 'a half'),
多半儿 (duōbànr, 'most likely / for the most part'),
后半儿 (hòubànr, 'the latter half').