Why is there a silent H in rhinoceros?

The silent "h" in "rhinoceros" is a result of the word's etymology and its origins in Greek. The word "rhinoceros" comes from two Greek words: "rhino" meaning "nose," and "keras" meaning "horn." In Greek, the initial "h" in "keras" is not pronounced, and this feature has been retained in the English adaptation of the word.

When words are borrowed from other languages, their pronunciations and spellings may undergo changes based on the linguistic patterns of the borrowing language. In this case, English adopted the word from Greek, maintaining the silent "h" in the process.

So, the silent "h" in "rhinoceros" is a reflection of the word's Greek origin and the tendency to preserve certain features of the original pronunciation when borrowing words into English. 

Here’s some more examples:

• Rhetoric: From the Greek word "rhetorike," meaning the art of effective or persuasive speaking or writing.

• Rhapsody: Derived from the Greek "rhapsōidia," referring to the epic poems sung by ancient Greek bards.

• Rhyme: Comes from the Greek word "rhythmos," meaning measured motion or flow, which evolved into referring to the repetition of sounds in words.

• Rhythm: Similar to "rhyme," it also has its roots in the Greek word "rhythmos" and relates to the pattern of beats or movements in music or poetry.

• Rhombus: From the Greek "rhombos," referring to a shape with all sides equal, opposite sides parallel, and opposite angles equal.

• Rhodium: Derived from the Greek word "rhodon," meaning rose, it is a metallic element often used as a plating material.