Verb

1. To cause (something) to become more glad.
   • 1798: William Wordsworth, The Nightingale http://etext.lib.virginia.edu/etcbin/ot2www-pubeng?specfile=/texts/english/modeng/publicsearch/modengpub.o2w&act=surround&offset=751382270&tag=Wordsworth,+William:+Lyrical+Ballads,+1798&query=+gladden&id=Wor2Lyr

     A balmy night! and tho' the stars be dim,

     Yet let us think upon the vernal showers

     That gladden the green earth, and we shall find

     A pleasure in the dimness of the stars.

   • 1838: Charles Dickens, Oliver Twist http://etext.lib.virginia.edu/etcbin/ot2www-pubeng?specfile=/texts/english/modeng/publicsearch/modengpub.o2w&act=text&offset=266704619&textreg=2&query=+gladden&id=DicOliv

     Her body was bent by age; her limbs trembled with palsy; her face, distorted into a mumbling leer, resembled more the grotesque shaping of some wild pencil, than the work of Nature's hand. Alas! How few of Nature's faces are left alone to gladden us with their beauty!

2. To become more glad in one's disposition.
   • 1470: Thomas Malory, Le Morte d'Arthur http://etext.lib.virginia.edu/etcbin/ot2www-pubeng?specfile=/texts/english/modeng/publicsearch/modengpub.o2w&act=text&offset=456406326&textreg=2&query=+gladden&id=Mal2Mor

     In May when every lusty heart flourisheth and bourgeoneth, for as the season is lusty to behold and comfortable, so man and woman rejoice and gladden of summer coming with his fresh flowers...