1.  osculation(n = noun.state) - (mathematics) a contact of two curves (or two surfaces) at which they have a common tangent;
is a kind of contact
Derived form verb osculate₂

2.  osculation(n = noun.act) buss, kiss - the act of caressing with the lips (or an instance thereof);
is a kind of touch, touching
has particulars: smack, smooch, deep kiss, french kiss, soul kiss
Derived form verb osculate₃

1.  The act of kissing; a kiss. [1913 Webster]

2.  The contact of one curve with another, when the number of consecutive points of the latter through which the former passes suffices for the complete determination of the former curve. Brande & C. [1913 Webster]

N  contiguity, contact, proximity, apposition, abuttal, juxtaposition, abutment, osculation, meeting, appulse, rencontre, rencounter, syzygy, coincidence, coexistence, adhesion, touching, (touch), borderland, frontier, tangent, abutter, contiguous, touching, in contact, conterminous, end to end, osculatory, pertingent, tangential, hand to hand, close to, with no interval.

N  endearment, caress, blandishment, blandiment, panchement, fondling, billing and cooing, dalliance, necking, petting, sporting, sparking, hanky-panky, caressing, embrace, salute, kiss, buss, smack, osculation, deosculation, amorous glances, courtship, wooing, suit, addresses, the soft impeachment, lovemaking, serenading, caterwauling, flirting, flirtation, gallantry, coquetry, true lover's knot, plighted love, love tale, love token, love letter, billet-doux, valentine, honeymoon, Strephon and Chloe, caressing, sighing like furnace, love-sick, spoony, caressed, faint heart neer won fair lady, kisses honeyed by oblivion.