Theory:

Meanings of difficult words from the poem "The Quarrel" by Eleanor Farjeon.
  
No.WordMeaning
1
SiblingsAny number of brothers and sisters within a family.
2
ComposerA person who creates music and songs based on them.
3
AutobiographyThe life history of any person, written by the same person.
4
Sibling rivalryFights happening between brother and sisters of the same family.
5
CompanyThe presence of others around a person.
6
To break outTo suddenly happen without any warning.
7
EscalateTo become very big very quickly.
8
Fall outWhen two persons don't agree to each others' ideas.
9
DefendTo speak in favour of a person's side.
10
One thing led to anotherA series of things happening very quickly.
11
To be absorbedGiving all of a person's attention to the matter.
12
DuskAnother word for evening.
13
ThumpingA friendly pat, generally on the back.
14
GrudgeTo hold anger against a person.