Several answers the question "how many?" — it means more than two but not a great number: "I've sent several emails this week". Severe answers "how bad?" — it means extreme, harsh or serious: "severe weather is forecast". The similar spelling is the only thing linking them; the meanings do not overlap at all.
Quantity versus intensity
Several is a determiner and pronoun of quantity. It sits before a plural countable noun — several people, several attempts, several of them — and implies a small but indefinite number, usually understood as three to about six or seven. It never describes how strong or serious something is.
Severe is an adjective of degree. It can describe conditions (severe frost), consequences (severe damage), symptoms (severe pain), rules (severe restrictions) or manner (a severe expression). It cannot be counted and never precedes a plural noun as a quantity word.
Each in a sentence
- "We interviewed several candidates before deciding."
- "Several of the panels had come loose."
- "The storm caused severe flooding along the coast."
- "She has a severe allergy to shellfish."
The test
Substitute a few. If the sentence still works — "we interviewed a few candidates" — the word is several. Now substitute serious. If that works — "serious flooding" — the word is severe. No sentence accepts both.
For spelling, note the ending: several counts things and shares its ending with total and numeral; severe ends in a silent e, like extreme and intense, the words it means.
Adverbs and the odd one out
The adverb of severe is severely — "severely damaged", "severely restricted". There is also a word severally, but it is not the adverb of several in any ordinary sense: it survives almost only in legal English, in the phrase jointly and severally liable, where it means separately or individually. If you are not writing a contract, you will not need it. To express "several times", say several times — never "severally".
Where the mix-up happens
Because the two words differ by one letter and share a sound, the error usually appears in fast typing or in second-language writing: "we had severe meetings about it" or "a several headache". Both read as obvious slips once spotted, but a spell-checker will pass them, since both are real words. When proofreading, ask of each one whether the sentence is counting or grading.
Frequently Asked Questions
How many is "several"?
More than two, but not many — most readers take it as roughly three to seven. If the exact number matters, give the number rather than the word.
Is it "severe pain" or "several pain"?
Severe pain. Pain is uncountable here and you are describing intensity, not quantity. "Several pains" would mean distinct instances of pain, which is a different claim.
Is "severally" the adverb of several?
No. Severally is a legal term meaning individually or separately, as in "jointly and severally liable". For the quantity idea, write "several times" or "in several cases".