In honor of Shavuot, lets look at a staple dairy food: chemah (or chem'ah) - חמאה. In Modern Hebrew this always refers to butter, but in Biblical times that wasn't necessarily the case. In Bereshit 18:8, Avraham is going to serve chemah to his guests. Rabbi Aryeh Kaplan, in The Living Torah , translates chemah as "cottage cheese", and writes:

Chemah in Hebrew, usually translated as curd. It is something that can be eaten alone; see Isaiah 7:15, 7:22; cf. Proverbs 30:33. Others interpret it to denote a kind of leben or yoghurt. According to Rashi, the word chemah denotes cream. (cf. Targum and Judges 5:25). The Septuagint, on the other hand, translates it as butter. Indeed, in Middle Eastern lands, it was the custom to eat butter alone.

So we see a pretty wide range of dairy products as possible translations. Klein says that the word chemah is related to the Arabic hami'a - "it was turbid". According to this site:

As the word chemah, here translated butter, signifies disturbed, agitated, probable that buttermilk is intended. The Arabs form their buttermilk by agitating the milk in a leathery bag

This fits in well with the parallel given in Mishlei 30:33 -

כִּי מִיץ חָלָב, יוֹצִיא חֶמְאָה-- וּמִיץ-אַף, יוֹצִיא דָם;וּמִיץ אַפַּיִם, יוֹצִיא רִיב.

"'The churning of milk brings forth butter, the wringing of the nose brings forth blood, and the forcing of anger brings forth strife"

While some of the kinship terms we've looked at so far have changed their meanings over time, we haven't seen a basic term that needed to be "invented". However, in 1943, the Jewish National Fund (KKL) asked the Vaad HaLashon for a Hebrew term that to us might seem obvious - nephew.

In this letter, they write (my translation):

In the listings in the memorial books of the KKL, it is customary to note the relationship between the dedicators and the dedicatees, as in: So-and-so is recorded by his parents, brother, etc ... It is not clear to us if the word nin נין means the son of the grandson or granddaughter, which is the popular usage, but is opposed to the opinion of the commentators.

Also, as to the new words dodan דודן and achyan אחין - it is questionable whether to accept them, and if we do, what is their feminine form.

The question was put to a committee headed by Tur-Sinai. In response, they wrote a dictionary of family terms, which can be found on this site (unfortunately, I can't link directly to it - to access it, click on the link הצגת מלון on the right, and then in the drop down menu choose משפחה).

Most of the terms in the dictionary just have a simple translation - English to Hebrew / Hebrew to English. But a few of them have notes - with the longest one being for their translation of "nephew". They translate nephew as nechdan נכדן (and niece as nechadnit נכדנית) and write: