For those have read The Adventures of Tom
 

In the verse is mentioned of Tom's Uncle Tim. The name probably was there for the rhyme, but do you also think that JRRT meant it for real?

I think I do!

I suppose it is possible to have an uncle who is younger than you.... However, such things normally require parents. Could Tom have been 'Eldest and Fatherless' and yet not 'Eldest and Uncleless'?

-Voronwe

Well, you certainly cannot use Our Logic to explain such matters in Middle-earth. Tom doesn't need parents to be a being, but he can have an uncle if Tolkien wanted him to!

I haven't read the "Adventures", but I'll run the hazardous risk of mentioning that "Uncle" is often used as a term of respect and endearment towards one who isn't necessarily a blood-relative.

Time for a resurrection. It's been a long while since this question was asked, but perhaps some other people have felt the same confusion.

It appears that the poem in question is No. 7, The Stone Troll.

As it happens, we can't take "Uncle Tim" as a mere respectful term of endearment, because in the fourth stanza we have
The explanation is quite simple. Not all of the poems in Adventures are about Tom Bombadil, which makes it quite a misleading title. Tolkien, in the character of an editor, explains their various origins in the preface to the collection.
This poem was adapted from a much earlier verse called The Root of the Boot, which Tolkien wrote while teaching at Leeds. The protagonist's name is unchanged from this first version, which was composed a little earlier than Tom Bombadil's first appearance (in The Oxford Magazine, Vol. 52 No. 13, 15th February 1934).

Of course, just the few lines quoted above will identify this poem to most people as the one Sam recites in The Flight to the Ford. The name of the protagonist is coincidental, having been a very common personal name for centuries.

Indeed. "Tom" is a nickname for "Tolman" in the Shire, and it would seem that "Tom" was common enough in Shire usage for it to be the name given by the local hobbits to the odd person living on their eastern border.
Whence "Bomdadil", though? ;)

By the conceit of translation, 'Bombadil' must be Tolkien's cod-Middle-English translation of the true Hobbitish name given to Iarwain Ben-adar. It could, of course, be an untranslatable nonsense-name (as Took), but - especially in light of the fact that he at one point calls himself 'Tom Bombadillo' - it seems entirely plausible that the Shire-folk created it from the Hobbitish Westron words for 'bombast' and 'peccadillo'. In other words: he's loud, he's weird, and there's something just a little bit wrong with him. ;)

hS

Whence Bombadil?
 

There is a possibility that a sense was originally intended, since Tolkien usually has something to say when he names somebody.

Tom Bombadil as a name first turns up in the early '30s, in a poem quoted in HME6 (p.115).
There is no river anywhere that has all of these place-names represented along it, so another purpose is being served. It's useful to analyse the onomastics of this second verse.

Long Congleby is not a real place-name. Its second element is from Old Norse -by ('enclosure'). There is a town in Cheshire called Congleton, which means 'Farmstead at the round-topped hill'. 'Long' is a vaunting later addition where present in an English place-name, but there is no Long Congleton in England either. 'Long farmstead by the round-topped hill'. Possibly 'long' is intended to be oxymoronic when paired with congel.

Stoke Canonicorum is a real place: Stoke Canon at the confluence of the Exe and Culm in Devon. Stoke - 'Outlying farmstead'. Canonicorum (Lat. 'of the Canons') was added later to denote ownership.

King's Singleton - I could find two Singletons in England: it means 'Farmstead with shingled roof' (Lancashire) or 'Farmstead near a burnt clearing' (West Sussex). 'King's' would have been added later to denote ownership, if any such place as King's Singleton existed.

Bumby Cocalorum is obviously not a real place-name. The first element is probably bumbay - 'a quagmire from stagnating water, dung etc' modified to look like a place-name ending in -by. Cocalorum survives in the obsolete playground game of High Cockalorum, which was abolished from schools in the 1950s for being too dangerous. It means 'playful and arbitrary', but cf Dutch cockeloeren - 'to crow'. In other words 'Crow on one's own dunghill'.

Tolkien is ridiculing the number of English place-names that have been altered from the Norman period onwards so that their lords and masters could show off. It's also probably significant that all of the place-names contain elements meaning 'farmstead', which could indicate that Tolkien thought they were putting on airs by talking about kings and canons. Therefore the personal names are going to tie in with that overall theme.

Pompadour is unattested before 1750 and refers directly to the Marquise de Pompadour (1721-64), the mistress of Louis XV. The word usually is used to describe the fashions of her era, but could also indicate courtly frou-frou ridiculousness at a stretch. Tolkien is highly likely to have investigated the origins of the word pompadour, which would explain his idiosyncratic spelling. In France, a Pompadour would be an inhabitant of Pompadour in Corrèze, one of the oldest manors in the department. It was common in English to attach a common first name to a descriptor like this to refer to a type of person. The etymology of this place-name is hard to pin down, but is probably related to pompe - 'pomp', 'magnificence', from Greek pompe - 'solemn procession, display'. Tolkien could also be referring obliquely to the fact that the Marquise contributed funds for the first two volumes of Diderot and D'Alembert's encyclopædia. It's probably worth noting that Tolkien's friend W.H. Lewis was an historian of ancien régime France.

For Bombadil, then, we have a few options, most of them related to bombast. Unusually for Tolkien it looks as though we have a real live French origin.

Bombance: Variant of bobance - 'boastfulness, ostentation'. 'Of uncertain origin.' There are three words likely to get JRRT's attention for a start.

Bombaceous: Latin bombyx 'silk'. 'Of or pertaining to plants of the genus Bombax, or the Silk-cotton family'. I threw this one in because of the reference to the Cotton family.

Bombace (1)The down of the cotton plant, (2) Cotton fibre dressed for stuffing or padding garments (3)Padding, stuffing cf bombast.

Bombard (sense 4): a deep-toned musical instrument of the bassoon family or sense 5: bombard-man - a servant who carried out liquor to customers; a pot-boy.

I'm inclined towards bombance, because the theme of the poem is the boastful origins of place-names and it fits nicely with 'Pompador'. I do like the pot-boy idea too, though.

Then again, Bombadil could simply be a nonsense name, coined not by Tolkien but by little Michael, the original doll's owner.