final particle / suffix, placed after many commonly used nouns to avoid employing one-syllable terms in speech (very common in the Beijing dialect 北京話, see: 兒化, 兒化韻)
"藍天高高雲兒飄飄" --> "High, high blue sky, little cloud float around"
The dictionary only mentioned 兒 can be used as a suffix, placed after many commonly used nouns to avoid employing one-syllable terms in speech.
In my opinion, adding the 兒 suffix to an object, can also humanize the object. For example, calling a goat '羊兒' or '羊羊' instead of '羊' give it a hint of youthful, human character. (like in typical baby talk)