types of vegetable

broccoli

broc·coli   [ˈbrɒkəli]    [ˈbrɑːkəli]  noun

uncountable
a vegetable with a thick green stem and several dark green or purple flower heads 
Word Origin:

[broccoli] mid 17th cent.: from Italian, plural of broccolo ‘cabbage sprout, head’, diminutive of brocco ‘shoot’, based on Latin brocchus, broccus ‘projecting’.

onion

onion [onion onions]   [ˈʌnjən]    [ˈʌnjən]  noun

countable, uncountable
a round vegetable with many layers inside each other and a brown, red or white skin. Onions have a strong smell and flavour
• Chop the onions finely.
• French onion soup  
Word Origin:
Middle English: from Old French oignon, based on Latin unio(n-), denoting a kind of onion.  
Example Bank:
• Garnish with a little chopped onion.
• Put the chopped onion and garlic in the pan…
• a jar of pickled onions
• cheese and onion flavoured crisps
• sage and onion stuffing

• the onion domes of St Basil's Cathedral

tomato

to·mato [tomato tomatoes]   [təˈmɑːtəʊ]    [təˈmeɪtoʊ]  noun

countable, uncountable (pl. to·matoes)
a soft fruit with a lot of juice and shiny red skin that is eaten as a vegetable either raw or cooked
• a bacon, lettuce and tomato sandwich
• sliced tomatoes
• tomato plants  
Word Origin:
early 17th cent.: from French, Spanish, or Portuguese tomate, from Nahuatl tomatl.  
Example Bank:

• Demonstrators threw rotten tomatoes at the car.

potato

po·tato [potato potatoes]   [pəˈteɪtəʊ]    [pəˈteɪtoʊ]  noun

countable, uncountable (pl. po·tatoes)
a round white vegetable with a brown or red skin that grows underground as the root of a plant also called a potato
• Will you peel the potatoes for me?
• roast/boiled/baked/fried potatoes

Word Origin:
mid 16th cent.: from Spanish patata, variant of Taino batata ‘sweet potato’. The English word originally denoted the sweet potato and gained its current sense in the late 16th cent.  
Example Bank:
• a plate of fried potato skins
• baked potatoes with sour cream and chives

• potatoes baked in their jackets