Gerund is the -ing form of the verb functioning as a Noun.
Look at the sentences below:
a. Walking is good for health.
b. Reading makes a man wise.
In these sentences, 'walking' and 'reading' are functioning as subject of the verbs 'is' and 'makes' respectively and hence they are functioning as Noun, these are Gerund.
Look at the following sentences:
a. We loves running through an open field.
b. We enjoy watching birds.
In these sentences, 'running' and 'watching' are functioning as Object of the verbs 'loves' and 'enjoy' respectively and hence they are functioning as Noun; these are Gerunds.
Look at the following sentences:
a. Seeing is believing.
b. Becoming a good citizen is contributing wealth to a country.
In these sentences, 'believing' and 'contributing' are functioning as complement of the verbs 'is' and are functioning as Noun; these are Gerunds.
Look at the following sentences:
a. Suresh is confident of doing well in the examinations.
b. He insists on resigning from the job.
In these sentences, 'doing' and 'resigning' are functioning as Object of the prepositions 'of' and 'on' respectively and hence they are functioning as Noun; these are Gerunds.
In such compound Nouns like 'turning-point', 'writing table', 'walking sticks', 'turning', 'writing' and 'walking' are Gerunds.