If a pullover sweater is a “jumper”, what’s a zip-up-the-front sweater called? What if it has a hood like this?
A jumper is also called a pullover here. A similar garment that buttons or zips at the front is called a cardigan. If it’s made of sweatshirt material, it’s a tracksuit top, if it also has a hood, it’s a ‘hoody’(sp?). Knitted cardigans with hoods are just hooded cardigans, AFAIK.
“Sweater”, “jumper” and “pullover” are pretty much synonymous in British English. The first two are more common, and in my experience “sweater” is more usual than “jumper”, although that could vary by region.
I’m English, and I hardly ever hear “sweater” except from Americans.
I make a distinction between a jumper and a pullover, a jumper is a much thicker and warmer garment. A pullover frequently, but not always, has a V-neck. A pullover might be worn over a long-slleved shirt with a collar, but a jumper would be worn over a t-shirt.
The term Jersey is also common.
Ditto what Peter says. I hardly ever used ‘sweater’.
A pullover is something a school aged child may wear (if they have a uniform).
Good picture here: http://www.unterseer.de/pro_sho_pu.htm
A jumper would be thicker. Something my old Mum would knit and force me to wear 
Thanks! So the knit-of-wool zip up the front with a hood is simply a hooded cardigan? (WhyDad was being silly and “posh” last night and told the baby to get her “jumper” and I said I didn’t think that was right. True anglophiles must get these piddly details right, you know! 
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Pretty much, yes, although the term ‘cardigan’ is falling out of favour - I wouldn’t be surprised to see it labelled in a shop as ‘hooded zip-front top’ or ‘knitted hoodie’, or something like that.
The cardigan itself (at least the buttoned, non-hoodie original) is falling out of favor, thanks to grandpa. You only have to get to page two of 175,000 Google Images hits before you start seeing cardigans. There are three on that page alone.
In the interests of science, I shall go over to M&S in a minute and see what the current retail terminology is. How’s that for SDMB service?
Fiver says this is an excuse to pick up a ready meal 
Tenner says he’s gone for a bottle of Chateau nuef Du Pape '57
…and a ready meal?
If they’re a lighter fabric they’re often called “sweatshirts”, or, in the horrible cataloguese phrase, “sweats”. As in “Hooded Sweat, £24.99”.
I got the ready meal and the Chateauneuf Du Pape ('61 actually) but forgot to look at the jumpers. Will try again later when I get my edamame and noodle lunch.
Dervla Kirwan on It’s not just a ready meal Dervla Kirwan off
There are not words for how much that advert annoys me. “These are not just potatoes, these are M&S pan-shaken potatoes with olive oil and rosemary”. So, actually, they are just potatoes, shaken in a pan with some stuff. <Must stop now before head explodes>
As a data point, in colloquial South African, a sweater is what you call a t-shirt.
A pullover jumper is called a jersey. Either v-neck, crew-neck or polo, depending. A poloneck is a turtleneck to the Yanks. A polo shirt is a golf shirt here.
I wouldn’t call it a cardigan if it didn’t have buttons. I’d call that a zip-up jersey or zip-up knitted top.
In America…these are jumpers.
I have been boggled for ages as to why they were so popular in England.
Now I know…they’re not! 
‘Sweat top’ seems to be the preferred terminology on M&S’s website.
Who is Dervla Kirwan and why does her name look better spelled backwards (Alvred Nawrik)?