  We study anomalous gauge-boson couplings induced by a locally SU(2) x U(1)
invariant effective Lagrangian containing ten operators of dimension six built
from the boson fields of the Standard Model (SM) before spontaneous symmetry
breaking (SSB). After SSB some operators lead to new three- and
four-gauge-boson interactions, some contribute to the diagonal and off-diagonal
kinetic terms of the gauge bosons and to the mass terms of the W and Z bosons.
This requires a renormalisation of the gauge-boson fields, which, in turn,
modifies the charged- and neutral-current interactions, although none of the
additional operators contain fermion fields. Bounds on the anomalous couplings
from electroweak precision measurements at LEP and SLD are correlated with the
Higgs-boson mass m_H. Rather moderate values of anomalous couplings allow m_H
up to 500 GeV. At a future linear collider the triple-gauge-boson couplings
gammaWW and ZWW can be measured in the reaction e+e- --> WW. We compare three
approaches to anomalous gauge-boson couplings: the form-factor approach, the
addition of anomalous coupling terms to the SM Lagrangian after and, as
outlined above, before SSB. The translation of the bounds on the couplings from
one approach to another is not straightforward. We show that it can be done for
the process e+e- --> WW by defining new effective ZWW couplings.
