After discussing shofar, we'll now talk about a synonym - yovel יובל. We find yovel being used as another term for a shofar in Shmot 19:13:
בִּמְשֹׁךְ, הַיֹּבֵל, הֵמָּה, יַעֲלוּ בָהָר - "When the yovel sounds a long blast, they may go up the mountain."
How do we know that yovel refers to a ram's horn? We see in Yehoshua chapter 6 that the yovel is an animal. And Rabbi Akiva in Rosh HaShana 26a says:
"When I visited Arabia I discovered that there they call the male ram 'Yovela'"
Steinsaltz points out that the word yovela does not appear in Arabic. However, it does appear with that meaning in Phoenician and Punic (for example in the Punic Marseilles Tariff, line 7.) Kutscher points out that the region called "Arabia", actually meant Arabia Petraea, whose capital was the famous town of Petra, where they spoke a dialect of Aramaic-Hebrew.
Klein writes that yovel's meaning of ram derived from the root יבל, meaning "to bear, carry" and therefore the word originally meant "leader of the flock, bellwether".
So yovel at first meant "ram", and the meaning was later limited to "ram's horn". The word's meaning developed even further. In Vayikra 25 we have the description of a special year of emancipation, held every 50 years. The advent of the year was proclaimed by the sounding of the shofar (Vayikra 25:9), and was called the yovel (25:10). So, as Kutscher points out, when the Torah discusses the yovel, it really means "[the year of the blowing of the] yovel." (For further discussion, see Ibn Ezra and Ramban on 25:10).
The Hebrew word made its way into Greek - iobelos and iabelaios - and from there to Latin - jubilaeus. From here we get the English word jubilee, which was influenced by an unrelated Latin word - jubilare (source of jubilant), meaning "to call to someone" and later "to shout for joy". Kutscher writes that the later meaning of jubilare might have been influenced by the joyous nature of the yovel year, but certainly the word jubilee has a festive connotation, due to convergence of two similar sounding words. From Latin the word entered European languages with a meaning of "celebration of an anniversary" - often 50 years, but not always (as discussed here.) Modern Hebrew has adopted the European sense of the word, and a yovel can mean the marking of any anniversary.
On a personal note, our son was born in 1998 - the 50th year of the founding of the State of Israel. We considered naming him Yovel, but figured that without nikkud, he would be more often called by the popular Hebrew name Yuval. At the time, I didn't think Yuval was related to yovel, but in researching this post, I have found a connection. Yuval was the son of Lemech, and was known as "the ancestor of all who play the lyre and the pipe" (Bereshit 4:21). The Daat Mikra mentions a number of theories as to the origin of his name. One of them makes a connection between Yuval and yovel - an early musical instrument.