I wouldn’t put it past Lady Catherine to inspect Charlotte’s pantry.....

To your question: look at this extract from Maggie Lane’s book Jane Austen and Food, which explains some of the difficulties correctly defining the food eaten on visits or during the mid point of the very long Georgian morning, and also explains the habit of offering cold cuts of meat to visitors :

I will return to the subject of dinner and its timing, but the point to be made first is that as the meal grew further and further away from breakfast, so some sustenance was required to fill the gap. The name of the snack or meal which came to occupy this slot seems to have a dual provenance.

Dr Johnson's Dictionary of 1755 defines 'lunch' or 'luncheon' as 'as much food as one's hand can hold': a pie, pasty or hunk of bread would fit this category, and no time is specified for eating it. Henry Brooke uses the word in this sense in The Fool of Quality, written in 1760, when he writes 'A large luncheon of brown bread struck my eyes'. Johnson's Dictionary has also an entry for 'nunchin' as 'a piece of victual eaten between meals'. The etymology of this derives from 'noonshine', meaning a drink, and by extension a snack, taken at noon.

Another variation is 'nooning', used by Susanna Whatman in 1776, both of which tie the word to a time of day more closely than DrJohnson's definition.

Jane Austen uses the word 'noonshine' in a letter written in June 1808 from Godmersham:

'The Moores came yesterday in their Curricle between one & two o'clock, & immediately after the noonshine which succeeded their arrival, a party set off for Buckwell. . . '(L, 195)

'Noonshine' was easily corrupted into 'nuncheon', which word Jane Austen uses on just one occasion, in Sense and Sensibility, to describe the hasty meal of cold beef and porter which Willoughby swallows at Marlborough on the road from London to Cleveland. From nuncheon to luncheon was an easy next step, and thus noonshine and lunch conjoined - semantically as well as conceptually. The word 'luncheon' is likewise used only once by Jane Austen. In Pride and Prejudice, when Elizabeth and Jane travel back from London, Lydia and Kitty meet them with the family carriage at the George Inn in an unnamed town, and order 'the nicest cold luncheon in the world', which consists of 'a sallad and cucumber' and 'such cold meat as an inn larder normally affords'. (P& P. 222, 219)

It is interesting, perhaps significant, that both these instances refer to meals taken at an inn. Jane Austen never uses the terms, either in letters or novels, when food is taken in the home at midday.

Caroline Austen refers to 'luncheon' at Chawton Cottage, and the division it made in the way her aunts' activities were arranged: 'working' before luncheon, walking or shopping afterwards - but she is almost certainly imposing her own later terminology.) The verb 'to lunch' did not appear until the 1830s and was at first considered very much a vulgarism.

During Jane Austen's lifetime, in a domestic context, refreshments would be offered without giving them any name, an awkward state of affairs which could not, and evidently did not, long continue.

So when Mr Knightley and Mrs Elton discuss the arrangements for the strawberry party to Donwell, they manage to do so without the word 'luncheon' ever passing their lips: 'cold meat' and 'a great set-out' are their respective expressions, while their author merely refers to 'the cold repast'. (E, 355, 361)

Similarly, when the party of Bertrams and Crawfords set off after breakfast to drive the ten miles to Sotherton, they are taken almost immediately on arrival into the dining-parlour, 'where a collation was prepared with abundance and elegance', before beginning their tour of the house and garden (MP, 84).

And when Elizabeth and Mrs Gardiner pay a morning call on the ladies of Pemberley, the first awkward attempts at conversation are relieved by 'the entrance of the servants with cold meat, cake, and a variety of all the finest fruits in season'. (P&P, 268)

These are very formal occasions. Much more relaxed and friendly is the series of visits Edmund pays to Mansfield Parsonage to hear Mary Crawford play the harp, when sustenance is provided (in the same room) by 'the sandwich tray, and Dr Grant doing the honours of it'. (MP, 65) At Godmersham, too, a tray, its burden unspecified, would be brought in to the company in the middle of the day.

The case seems to be that, except on the most formal occasions, such food was eaten not in the dining-room, but in whichever room the family used for sitting in the morning. ..*spoiler removed-JW*.

As the meal had no name, it is not surprising that it had no fixed hour but was offered whenever guests appeared. There was never a definite invitation to 'come for lunch at one', for example. Indeed, the food might make its appearance more than once, if there was a series of callers. This is certainly the case in the humble Bates household, where on different occasions baked apples and 'sweet-cake from the beaufet' are pressed on their visitors. 'Mrs Cole had just been there, just called in for ten minutes, and had been so good as to sit an hour with them, and she had taken a piece of cake and been so kind to say she liked it very much….

Even if no visitors called, the family would require some refreshment between dinner and breakfast, but Jane Autsen rarely considers it worthy of mention. Two instances are given very much in passing. One is the “cold meat’ eaten at Northanger Abbey between morning and evening service on a Sunday . The other occurs soon after Anne Elliot’s Arrival at Uppercross
pages 34-36