Gnomish
nôs
noun. birthday; nature
noss
noun. rain
nôs mora
good by nature
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
A word appearing as G. {noss >>} nôs “birthday” in the Gnomish Lexicon of the 1910s (GL/61), clearly based on the early root ᴱ√NŌ “become, be born” (QL/66). In the contemporaneous Gnomish Grammar it appeared with the gloss “nature” in phrases like nôs mora “good by nature” (GG/10).
Neo-Sindarin: The usual Neo-Sindarin word for “birthday” is ᴺS. oronnad, a combination of aur “day” and [ᴺS.] onnad “birth”. The word has been floating around for long enough that I have no idea where it originated, but I first learned of it from Fiona Jallings’s Sindarin word lists.