How can I wrap text into two columns?

Using the -COLUMN or --columns=COLUMN option of pr

-COLUMN, --columns=COLUMN
       output COLUMN columns and print columns down, unless -a is used.
       Balance number of lines in the columns on each page

so either

pr -t -2 yourfile

or

pr -t --columns=2 yourfile

For example, augmenting your entries with some random dictionary words,

$ cat << EOF | pr -t -2
> apple
> banana
> `shuf -n28 /usr/share/dict/words`
> grape
> guava
> EOF
apple                               overachieves
banana                              wickerwork
cottonmouths                        supersonic
adapter's                           draftiest
boudoir's                           insisting
cruised                             programs
mousetrap                           parcel
shticks                             basically
TLC's                               coruscates
conduction                          Jones
geeing                              Ty
gloamings                           bondage
investing                           candelabra's
radiotherapists                     Inchon's
clasp's                             grape
critters                            guava

You can use the columns command from the autogen package, e.g.:

columns -c 2 -w 40 --by-column < input

For example:

{
  echo apple
  echo banana
  shuf -n28 /usr/share/dict/words
  echo grape
  echo guave
} |
columns -w 40 -c 2 --by-columns

Output:

apple                                   merwoman
banana                                  chiroplasty
antispreading                           stylommatophorous
spearmint                               Sphaerobolaceae
sulphoxyphosphate                       snark
nymphaeum                               reactionary
ahluwalia                               hobo
husky                                   oxamethane
crimeproof                              deltarium
cerebrosis                              hematoporphyrin
yoghurt                                 noncompoundable
colloquial                              sororially
unaffirmed                              nonobjection
saccharated                             reundercut
thermochemic                            grape
preobedience                            guave