that is to say

Adverb

WordNet 3.0

Adverb (1)

as followsSynonyms: namely viz.to wit videlicet

Webster's Dictionary (GCIDE)

Say \Say\, v. t. [imp. & p. p. Said (s[e^]d), contracted from sayed; p. pr. & vb. n. Saying.] [OE. seggen, seyen, siggen, sayen, sayn, AS. secgan; akin to OS. seggian, D. zeggen, LG. seggen, OHG. sag[=e]n, G. sagen, Icel. segja, Sw. s[aum]ga, Dan. sige, Lith. sakyti; cf. OL. insece tell, relate, Gr. 'e`nnepe (for 'en-sepe), 'e`spete. Cf. Saga, Saw a saying.]

1.To utter or express in words; to tell; to speak; to declare; as, he said many wise things. [1913 Webster]

Arise, and say how thou camest here.— Shak.[1913 Webster]

2.To repeat; to rehearse; to recite; to pronounce; as, to say a lesson. [1913 Webster]

Of my instruction hast thou nothing bated In what thou hadst to say?— Shak.[1913 Webster]

After which shall be said or sung the following hymn.— Bk. of Com. Prayer.[1913 Webster]

3.To announce as a decision or opinion; to state positively; to assert; hence, to form an opinion upon; to be sure about; to be determined in mind as to. [1913 Webster]

But what it is, hard is to say.— Milton.[1913 Webster]

4.To mention or suggest as an estimate, hypothesis, or approximation; hence, to suppose; -- in the imperative, followed sometimes by the subjunctive; as, he had, say fifty thousand dollars; the fox had run, say ten miles. [1913 Webster]

Say, for nonpayment that the debt should double, Is twenty hundred kisses such a trouble?— Shak.[1913 Webster]

It is said, or They say, it is commonly reported; it is rumored; people assert or maintain.

That is to say, that is; in other words; otherwise. [1913 Webster]